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NASA/TP-2003-212438 




Portable Wireless LAN Device and Two-Way 
Radio Threat Assessment for Aircraft 
Navigation Radios 



TruongX. Nguyen, Sandra V. Koppen, Jay J. Ely, 
Reuben A. Williams and Laura J. Smith 
Langley Research Center, Hampton, Virginia 



Maria Theresa P. Salud 

Lockheed Martin, Hampton, Virginia 



July 2003 



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NASA/TP-2003-212438 




Portable Wireless LAN Device and Two-Way 
Radio Threat Assessment for Aircraft 
Navigation Radios 



Truong X. Nguyen, Sandra V. Koppen, Jay J. Ely, 
Reuben A. Williams and Laura J. Smith 
Langley Research Center, Hampton, Virginia 



Maria Theresa P. Salud 

Lockheed Martin, Hampton, Virginia 



National Aeronautics and 
Space Administration 

Langley Research Center 
Hampton, Virginia 23681-2199 



July 2003 



Acknowledgments 

Special thanks is extended to United Airlines and Eagle Wings Incorporated for their technical support and 
for providing access to operational Boeing 737-200 and 747-400 aircraft in support of aircraft interference 
pathloss measurements. 

The authors wish to express their gratitude to Dave Walen, John Dimtroff, and Tony Wilson of the Federal 
Aviation Administration for their continuing support and technical direction. 

The authors are also appreciative of Drs. John Beggs, Manohar Deshpande, Robin Cravey, and Mr. Bruce 
Fisher for their assistance in technical and editorial editing. 

This work was funded by the Federal Aviation Administration as part of FAA/NASA Interagency 
Agreement DFTA03-96-X-90001, Revision 9, as well as the NASA Aviation Safety Program (Single 
Aircraft Accident Prevention Project) 



The use of trademarks or names of manufacturers in the report is for accurate reporting and does not 
constitute an official endorsement, either expressed or implied, of such products or manufacturers by the 
National Aeronautics and Space Administration. 



Available from: 



NASA Center for AeroSpace Information (CASI) 
7121 Standard Drive 
Hanover, MD 21076-1320 
(301)621-0390 



National Technical Information Service (NTIS) 
5285 Port Royal Road 
Springfield, VA 22 1 6 1 -2 1 7 1 
(703) 605-6000 



Table of Contents 



Table of Contents iii 

Acronyms vi 

List of Symbols viii 

1 Executive Summary ix 

2 Introduction 1 

2.1 Background 1 

2.2 Objective 3 

2.3 Approach 3 

2.3.1 Emission Measurements of WLAN Devices and Two- Way Radios 4 

2.3.2 Path Loss Measurements 5 

2.3.3 Safety Margin Calculations 6 

2.4 Report Organization 6 

3 WLAN and Radio RF Emissions 6 

3.1 Wireless Overview 6 

3. LI IEEE 802.11a 6 

3.1.2 IEEE 802.11b 7 

3.1.3 Bluetooth 7 

3.1.4 FRS/GMRS Radios 7 

3.2 Measurement Process 8 

3.2.1 Measurement Method 8 

3.2.2 Preliminary Testing 14 

3.2.3 Device-Focused Testing 23 

3.2.4 Data Reduction 35 

3.3 Test Results of WLAN Devices 36 

3.3.1 Band 1 (105 MHz to 120 MHz) 37 

3.3.2 Band 2 (325 MHz to 340 MHz) 40 

3.3.3 Band 3 (960 MHz to 1250 MHz) 43 

3.3.4 Band 4 (1565 MHz to 1585 MHz) 46 

3.3.5 Band 5 (5020 MHz to 5100 MHz) 49 

3.4 Summary of Emission From Standard Laptops and PDAs 52 

3.5 Comparison of Emissions From Intentionally- and Unintentionally-Transmitting 
PEDs 55 

3.5.1 Band 1 (105 MHz to 120 MHz) 55 

3.5.2 Band 2 (325 MHz to 340 MHz) 58 

3.5.3 Band 3 (960 MHz to 1250 MHz) 60 

3.5.4 Band 4 (1565 MHz to 1585 MHz) 63 

3. 6 Summary of Maximum Emissions from WLAN Devices and FRS/GMRS Radios 68 

3.6.1 Summary of Maximum Emission Results 68 

3.6.2 Comparison with Emission Limits 69 

3.6.3 Expected Directivity Estimation 72 



111 



4 Aircraft Interference Path Loss Determination 73 

4.1 Interference Path Loss Measurements onB737s andB747s 74 

AAA IPL Measurement Method 75 

4.1.2 Measured Interference Path Loss Resuhs 80 

4.2 Other Interference Path Loss Data 90 

4.3 Summary of Minimum Interference Path Loss Data 103 

5 Interference Analysis 103 

5.7 Published Receiver Susceptibility 103 

5. LI RTCA/DO-233 104 

5.1.2 RTCA/DO-199 104 

5.2 Safety Margin Calculations 105 

6 Summary and Conclusions 109 

7 References 110 

Appendix A: Measurement and Results of Intentional Transmitters Including WLAN 
Devices and Two- Way Radios Al 

A.l 802.1 la WLAN Devices A2 

AAA Bandl A2 

A.1.2 Band 2 A5 

A.L3 Bands A8 

A.1.4 Band 4 All 

A.1.5 Band 5 A14 

A.2 802.11b WLAN Devices A17 

A.2.1 Bandl A17 

A.2.2 Band 2 A21 

A.2.3 Bands A25 

A.2.4 Band 4 A29 

A.2.5 Band 5 A33 

A.3 Bluetooth Devices A37 

A.3.1 Bandl A37 

A.3.2 Band 2 A40 

A.3.3 Band 3 A43 

A.3.4 Band 4 A46 

A.3.5 Band 5 A49 

A.4 FRS Radios A52 

A.4.1 Bandl A52 

A.4.2 Band 2 A54 

A.4.3 Bands A56 

A.4.4 Band 4 A58 

A.4.5 Band 5 A60 

A.5 GMRS Radios A62 

A.5.1 Bandl A62 

A.5.2 Band 2 A64 

A.5.3 Bands A66 



IV 



A.5.4 Band 4 A68 

A.5.5 Band 5 A70 

Appendix B: Measurements and Results of Non-Intentional Transmitters Including 

Computer Laptops and Personal-Digital-Assistants Bl 

B.l Bandl Bl 

B.2 Band 2 B7 

B.3 Bands B13 

B.4 Band 4 B19 

B.5 Bands B25 



Acronyms 

AP Access Point 

ATC Air Traffic Control 

ATCRBS Air Traffic Control Radar Beacon System 

B737, B747 Boeing 737, 747 Aircraft 

BPSK Binary Phase Shift Keying 

COTS Commercial-Off-The-Shelf 

CW Continuous-wave 

dBi dB relative to isotropic reference pattern 

dBm dB relative to 1 milliwatt 

dB|LiV/m Field strength unit in dB relative to one |LiV/m 

DME Distance Measuring Equipment 

DSSS Direct Sequence Spread Spectrum 

DUT Device-Under-Test 

EE Emergency Exit 

EMI Electromagnetic Interference 

EUROCAE European Organisation for Civil Aviation Equipment 

EWI Eagles Wings Inc. 

FAA Federal Aviation Administration 

FCC Federal Communications Commission 

FHSS Frequency Hopping Spread Spectrum 

FRS Family Radio Service 

GFSK Guassian Frequency Shift Keying 

GHz Gigahertz 

GMRS General Mobile Radio Service 

GPS Global Positioning System 

GS Glideslope 

HIRE High Intensity Radiated Fields 

ICAO International Civil Aviation Organisation 

IEEE Institute of Electrical and Electronics Engineers 

ILS Instrument Landing System 

IPL Interference Path Loss 

ISM Industry, Scientific, and Medical 

ITU International Telecommunication Union 

LAPl-8 Laptop computers 1-8. See details in Table 3.2-4 

LaRC Langley Research Center 

LOC Localizer 



VI 



MAX Maximum 

MHz Megahertz 

Min. Minimum 

MIPL Minimum Interference Path Loss 

MLS Microwave Landing Systems 

MOPS Minimum Operating Performance Standards 

NASA National Aeronautics and Space Administration 

NIC Network Interface Card 

NIST National Institute of Standards and Technology 

PCMCIA Personal Computer Memory Card Interface Adapter 

PC Card PCMCIA Card 

PDA Personal Digital Assistant 

PED Portable Electronic Device 

PLF Path Loss Factor 

PRN Printer 

PS Ping Storm 

QAM Quadrature Amplitude Modulation 

QPSK Quadrature Phase Shift Keying 

RC Reverberation Chamber, or Mode-Stirred Chamber 

RF Radio Frequency 

RTCA RTCA, Inc. 

SAC Semi-anechoic Chamber 

SatCom Satellite Communication (Aeronautical Mobile Satellite Service) 

SD Secure Digital 

StDev Standard Deviation 

TACAN Tactical Air Navigation 

TCAS Traffic Collision - Avoidance System 

TCP/IP Transmission Control Protocol/ Internet Protocol 

TSO Technical Standard Orders 

UAL United Airlines 

UNII Unlicensed National Information Infrastructure Band 

US United States 

USB Universal Serial Bus 

UWB Ultrawideband 

VEE Visual Engineering Environment 

VHF Comm Very High Frequency Communication - Voice Modulation 

VHF-1 Comm VHF-Comm radio no. 1 

VOR VHF Omnidirectional Range 



vii 



WECA 

Wi-Fi 

WLAN 

WPAN 

Xfer 



Wireless Ethernet Compatibility Alliance 
Wireless Fidelity 
Wireless Local Area Network 
Wireless Personal Area Network 
Duplex File Transfer 



List of Symbols 



71 

A 

B 

C 

CF 

CLF 

Dg 

E 

EIRP 

IL 

L 



'Chmbr(dB) 



^RecCable(dB) 



^XmitCable(dB) 



^(2),^^3) 



^ SAMeas(dBm) 

^TotRad 
P 

R 

Rx 

S/I 

TRP 

Tx 



Universal constant = 3.141592654 

Transmit antenna efficiency factor 

Device emission power 

Interference coupling factor, negative of interference path loss in dB 

Receiver susceptibility threshold 

Chamber Calibration Factor (dB) 

Chamber Loading Factor 

Directivity 

Electric Field Intensity (V/m) 

Effective Isotropic Radiated Power (W) 

Empty chamber Insertion Loss 

Chamber loss (dB), or = -10togio( CLF * IL ) 

Receive cable loss (dB) 

Transmit cable loss (dB) 

Carrier frequency power 

Maximum received power measured over one paddle rotation 

Power received at points (2) and (3), respectively, in dBm 

Maximum receive power measured at the spectrum analyzer (dBm) over one stirrer 

revolution 
Power transmitted at point (1), in dBm 

Total radiated power within measurement resolution bandwidth 
Power transmitted from source (dBm) 

Distance (m) 

Receive 

Signal-to-Interference Ratio 

Total Radiated Power (within measurement resolution bandwidth) 

Transmit 



Vlll 



Abstract 

Measurement processes, data and analysis are provided to address 
the concern for Wireless Local Area Network devices and two-way 
radios to cause electromagnetic interference to aircraft navigation radio 
systems. A radiated emission measurement process is developed and 
spurious radiated emissions from various devices are characterized 
using reverberation chambers. Spurious radiated emissions in aircraft 
radio frequency bands from several wireless network devices are 
compared with baseline emissions from standard computer laptops and 
personal digital assistants. In addition, spurious radiated emission data 
in aircraft radio frequency bands from seven pairs of two-way radios are 
provided. A description of the measurement process, device modes of 
operation and the measurement results are reported. Aircraft 
interference path loss measurements were conducted on four Boeing 747 
and Boeing 737 aircraft for several aircraft radio systems. The 
measurement approach is described and the path loss results are 
compared with existing data from reference documents, standards, and 
NASA partnerships. In-band on-channel interference thresholds are 
compiled from an existing reference document. Using these data, a risk 
assessment is provided for interference from wireless network devices 
and two-way radios to aircraft systems, including Localizer, Glideslope, 
Very High Frequency Omnidirectional Range, Microwave Landing 
System and Global Positioning System. The report compares the 
interference risks associated with emissions from wireless network 
devices and two-way radios against standard laptops and personal 
digital assistants. Existing receiver interference threshold references are 
identified as to require more data for better interference risk 
assessments. 



1 Executive Summary 

Wireless technologies are widely adopted in the present consumer market. Technologies such as 
cellular phones and wireless local area networks (WLANs) have brought a revolution in accessibility and 
productivity. WLANs enable consumers to have convenient access to web-browsing, email, instant 
messaging and numerous enterprise applications. As travelers become more dependent upon Internet 
access, airlines are increasingly interested in providing connectivity to their customers while traveling 
onboard aircraft. While WLAN equipment provided by the airlines for permanent installation on the 
aircraft must be properly certified, passenger carry-on products are not required to pass the rigorous 
aircraft radiated field emission standards. 

Two-way radio communications, such as Family Radio Service (FRS) and General Mobile Radio 
Service (GMRS), are also becoming popular. These no-fee radio systems allow family members, friends 
and business associates to stay in contact during trips, shopping, or where party members may be 
physically dispersed. Unlike the low power FRS radios with half-watt maximum transmitted power. 



IX 



GMRS radio can radiate much higher power. Two-watt GMRS radio models, which require a hcense 
presently, are highly popular. Many recent models have both FRS and GMRS built-in features. While use 
of these radios is not presently authorized on aircraft, their low cost and popularity hint that their use by 
unsuspecting passengers is likely. 

With the support of the Federal Aviation Administration (FAA) Aircraft Certification Office and the 
National Aeronautics and Space Administration (NASA) - Aviation Safety Program - Single Aircraft 
Accident Prevention Project, radio frequency (RF) emissions from portable WLAN devices and two-way 
radios were measured. In addition, interference path loss (IPL) measurements were conducted with an 
airline partner to quantify the attenuation levels for emission from inside the passenger cabin. These 
emission and path loss data are used to assess potential risks to aircraft systems. 

This report documents the spurious radiated emission measurement process and shows the results from 
WLAN devices and two-way radio testing. Spurious emissions are emissions on frequencies that are 
outside the necessary bandwidth, and the level of which may be reduced without affecting the 
corresponding transmissions of information. Out-of-band emissions (emissions at frequencies 
immediately outside the necessary bandwidth) are excluded. The emission results are compared against 
emissions from standard laptop computers and Personal Digital Assistants (PDAs), which are used in this 
report as benchmarks, since these devices are currently allowed for use during certain non-critical phases 
of flight. In addition, the report documents IPL results measured on four Boeing B747-400 and six 
Boeing B737-200 aircraft. These airplanes were provided by United Airlines (UAL) for IPL 
measurements under a contract between NASA Langley Research Center (LaRC) and Eagles Wings 
Incorporated (EWI). The new IPL results are summarized and presented together with the existing IPL 
data from other sources, which include references, standards, and results from other NASA cooperative 
efforts. Interference thresholds summarized from an existing standard are reported. The measured 
emissions, the overall IPL, and the interference thresholds were used to compute interference safety 
margins reported in this document. The sections below provide additional details on the measurements, 
results and the analysis. 

Radiated Emission Measurement 

Radiated emissions from WLAN devices and two-way radios were measured in two reverberation 
chambers (RCs) at NASA LaRC. Two chambers were employed to overcome certain frequency and 
operational limitations associated with highly sensitive emission measurements. WLAN network 
interface cards (NIC), access points (APs) and a Bluetooth test set were acquired. Preliminary testing was 
conducted to identify WLAN operational issues in a high multi-path RC environment. The WLAN 
devices tested include seven Institute of Electrical and Electronics Engineers (IEEE) 802.11b, five IEEE 
802.11a, and six Bluetooth devices. As a result of the preliminary testing, WLAN operating modes, 
channels, and data rates were identified and uniformly adopted for more extensive tests. FRS and GMRS 
radio operations were simple and no such preliminary testing was needed. 

The preliminary testing also involved selecting host laptop computers and PDAs with low emissions 
so they did not mask emissions from the WLAN devices under test. The screening involved emission 
measurement of eight laptop computers and two PDAs in various operational modes. The host laptops 
and PDAs were selected using the criteria of the lowest emissions in the measurement frequency bands 
while operating in idle and file transfer modes. This screening identified two laptop computers to cover 
five measurement frequency bands and both PDAs. 



The RC emission measurement method used was adopted from an earlier effort to assess the risk of 
interference from wireless phones to aircraft radio receivers [1]. The RC method was efficient, 
repeatable, and provided results directly in terms of effective peak radiated power, rather than electric 
field strength, so that an approximate conversion from field strengths to radiated power was not needed. 
Proper use of filters prevented high power emissions from the WLAN devices at wireless carrier 
frequencies from reaching the receiver, preventing undesirable receiver overloading and intermodulation. 
Filters were also used to block spurious emissions from the WLAN AP antenna from radiating in the 
chamber and contaminating the environment. 

Interference Path Loss Measurement 

Path loss measurement was another major effort to help assess risks of interference to aircraft systems 
from passenger carry-on devices. The measurements were conducted on four Boeing 747-400 and six 
Boeing 737-200 airplanes provided by UAL during three one-week trips to Southern California Aviation 
facility in Victorville, California. Several aircraft systems were measured, including Localizer (LOC), 
Glideslope (GS), Very High Frequency Omnidirectional Range (VOR), Very High Frequency 
Communication (VHF-Comm.), Global Positioning Systems (GPS), Traffic Collision Avoidance System 
(TCAS), and Satellite Communication (SatCom). The measurements were conducted with a radiating 
antenna positioned at windows and doors, while a spectrum analyzer recorded the maximum signals 
coupled into aircraft antennas. The transmitting antenna was also positioned at locations other than 
windows and doors on two aircraft, and the end comparison indicates that the door and window 
measurements indeed capture the minimum IPL values. In addition, the results indicate that for many 
systems the minimum IPL is strongly influenced by the antenna locations relative to an aircraft door. 
Therefore, IPL for a particular aircraft is dependent upon antenna installation. The measured IPL data are 
summarized in this report along with other previously available IPL data, and the computed all-aircraft 
minimum IPL values are shown. 

Interference Safety Margin 

Interference analysis was conducted using the WLAN and two-way radios emission results, the IPL 
(all new and previously available data considered), and the receiver interference thresholds from a 
standard document. Interference safety margins were calculated for each combination of WLAN/radio 
device, minimum or average IPL, and minimum or typical interference threshold. As a result, the safety 
margin can be positive or negative. However, it was seen that WLAN devices, in general, have better 
safety margins than laptops and PDAs, mainly due to lower emissions in most cases. The FRS/GMRS 
radios have the worst safety margin in the GS band due to very high spurious emissions. The emissions 
are also high for FRS/GMRS radios in the Microwave Landing Systems (MLS) band. Yet, the results 
indicate a very large positive safety margin, and these radios are, therefore, not a concern in this band. 

Conclusions 

1. Spurious emissions in aircraft radio bands from selected WLAN devices were lower than from 
laptop computers and PDAs. One exception is IEEE 802.11a device emissions in the MLS band, 
where emissions from the laptop computers and other WLAN devices were too low to be 
measured. With that exception, the results indicate that the WLAN devices tested are not any 
more threatening to the aircraft bands under consideration than the common laptop computers and 
PDAs. High emissions from IEEE 802.11a devices in the MLS band are not a concern due to a 
very large positive safety margin. 



XI 



2. FRS/GMRS radio emissions are much higher than from the laptops/PDAs in the GS and MLS 
bands. In the GS band, emissions from GMRS/FRS radios can exceed the laptop/PDA maximum 
emission by as much as 30 dB, and the aircraft emission Hmit RTCA/DO-160 Category M by as 
much as 23 dB. In the MLS band, the maximum emissions from GMRS/FRS radios can exceed 
the laptop/PDA maximum emissions by at least 44 dB, but are below the RTCA/DO-160 Category 
M emission limit. 

3. Spurious emissions from WLAN devices are lower than Federal Communications Commission 
(FCC) Part 15 limits, but can be higher than aircraft RTCA/DO-160D Category M emission limits 
in the TCAS, Air Traffic Control Radar Beacon System (ATCRBS), and Distance Measuring 
Equipment (DME) bands. 

4. IPL measurements were conducted to supplement existing data. Analysis of new measurement 
data supports previous observations that window and door locations capture the lowest IPL values, 
and that proximity of aircraft antennas to an aircraft door can reduce minimum IPL significantly. 

5. Interference safety margin can be positive or negative, and can vary broadly depending on the IPL 
and interference threshold values used. 

Recommended Future Work: 

1 . Additional receiver interference threshold data are needed for greater confidence level. More tests 
on a number of receivers from multiple manufacturers are recommended. Signal modulation and 
types should be considered. 

2. Conduct emission measurements and interference analysis on other types of wireless devices, 
particularly those utilizing newly available RF bands and having multi-band capability. Some of 
the current and future wireless trends include 2.5G and 3G phones, software-defined-radios, 
phones/PDAs with built-in camera and other smart features. 

3. Assess the potential for emerging radio technologies that overlay existing spectrum (such as Ultra 
Wideband) to cause interference to aircraft systems. 

4. Conduct additional IPL measurements on different types of aircraft where minimal data currently 
exists. 

5. Initiate flight operational assessment of PED electromagnetic interference (EMI) to aircraft radios, 
addressing safety impact of EMI as affected by navigation data processing and redundancy 
management within specific avionics packages, including the influence of crew and air traffic 
control procedures. 



xii 



2 Introduction 

"All portable electronic devices must remain off during taxi, takeoff, approach, and landing until the 
plane arrives at the gate and the seat-belt sign is turned off." "Passengers may turn on and use cellular 
phones only when the main cabin door is open". "Any radio transmission using personal communication 
devices is prohibited". Such announcements are familiar to airplane travelers. These policies stem from 
the potential for portable electronic devices (PEDs) to interfere with aircraft communication and 
navigation systems, and are stated in a way that has been applicable to most commercially available 
products, until recently. With the introduction of increasingly compact, inexpensive, multifunction 
wireless PEDs, it is more difficult for passengers (and flight attendants) to determine if a device is acting 
as a transmitter. Sometimes it is ambiguous if a device is turned on at all. In fact, some new wireless 
technologies incorporate the ability to turn themselves on when packed away in a storage compartment or 
under a seat. 

Wireless technologies have brought a revolution in personal accessibility and productivity, and have 
created new markets for products and services. WLANs enable convenient and affordable web-browsing, 
email, instant messaging and numerous enterprise applications in high-traffic public places such as 
restaurants, coffee shops, shopping malls, convention centers, hotels, and airports. As travelers become 
more dependent upon Internet access at places away from home or office, airlines are becoming more 
interested in providing connectivity to their customers while traveling on board aircraft. 

The use of unauthorized intentional transmitters, such as WLAN devices, wireless phones and 
citizen's band radios are of growing concern to the FAA and to the airlines who are responsible for 
passenger safety. While WLAN equipment provided by the airlines for permanent installation on the 
aircraft must be properly certified, the passenger carry-on products are not required to pass the rigorous 
aircraft radiated-field emission standards. Demanding certification for use on aircraft is considered 
impractical due to enforceability issues that could result in poor customer relations. 

FRS and GMRS are becoming popular as family members, friends and business associates desire to 
stay connected during trips, shopping or where members may be physically dispersed. On an aircraft, 
unaware passengers may attempt to use these radios to communicate with others whose seats may be 
assigned at different locations on the aircraft. Use of these radios by American travelers/tourists has been 
observed in foreign countries where their use was not yet allowed. With two watts of radiated power, the 
GMRS radio is attractive due to extended range and increased channel capacity compared to the lower- 
power FRS radio. GMRS radio is readily available but requires a license to operate. However, it is 
unrealistic to assume that all users are aware of (or willing to comply with) the requirements of 
application submission and high fees. The popularity and low cost of the FRS and GMRS radios make it 
reasonable to assume that their use on airplanes by unsuspecting passengers is inevitable. 

2.1 Background 

This report builds upon a detailed threat assessment of wireless phones previously performed by 
NASA, and accomplishes objectives identified in the previous NASA work [1]. The previous NASA 
report introduced a radiated emission measurement process for two dominant digital standards for 
wireless handsets, and reported detailed radiated emission data for several typical units. The 
measurement technique was also different in that a new RC method was used that has certain advantages 
over conventional test methods. The wireless handset data was supplemented with detailed aircraft IPL 
and navigation radio interference threshold data from numerous reference documents, standards and 
NASA partnerships. The radiated emission measurement process, path loss data and interference 



threshold analysis are directly applied, and extended, for WLANs, Bluetooth devices and FRS/GMRS 
radios evaluated in this report. The previous NASA report drew extensively from RTCA Special 
Committee reports published in 1988 (RTCA/DO-199 [2]) and 1996 (RTCA/DO-233 [3]), which remain 
the foundation for regulatory and advisory guidance for the FAA and other comparable agencies 
worldwide. 

On July 12, 2001, the European Organisation for Civil Aviation Equipment (EUROCAE) held their 
initial meeting of Working Group 58, tasked to reexamine the issues of PEDs used onboard commercial 
aircraft. In their second meeting on September 20-21, 2001, the Group identified the following 
objectives: 

1. "To review the EMC issues related to the use of new technology PEDs and related installed 
services on aircraft by evaluation and comparison of existing studies, measurement of data as 
necessary, and production of a report." 

2. "To propose technical and non-technical solutions for the operation of PEDs on board aircraft for 
the aviation community, including standards and guidelines as appropriate." 

3. "To provide guidelines to non-aviation standardisation fora, in order to help them assist in the 
maintenance of safety on board aircraft." 

EUROCAE Working Group 58 agreed on the following initial Terms of Reference: 

1. Evaluate PEDs to identify new technologies, device types and their potential usage on aircraft. 

2. Evaluate services, provided by airlines and aircraft manufacturers, which may use non- 
aeronautical commercial-off-the-shelf (COTS) equipment. 

3. Consider both intentional and unintentional radiations from PEDs, and their coupling to 
electronic systems and antennas. 

4. Gather opinions and information from, and collaborate with, interested parties, including aircraft 
manufacturers, aviation equipment manufacturers, airlines, regulatory authorities and the 
electronics industry. 

5. Work jointly and establish close working relationships with the International Civil Aviation 
Organisation (ICAO) panels, coordinating groups, regulatory authorities and other standards 
organisations as appropriate. 

6. Produce guidance documentation in a timely manner and in an appropriate format for the use of 
those concerned with this issue. 

These initial Terms of Reference have been slightly modified, and the EUROCAE WG-58 activity 
continues. An Internet website has been established to consolidate documentation, agendas and schedules 
for this activity, but is accessible only to subscribers. 

On March 20, 2003, the RTCA established Special Committee 202, upon request from the FAA, to 
"develop guidance related to the use of portable electronic devices on board air carrier aircraft." The 
guidance "will provide a means for authorities, aircraft operators and aircraft manufacturers to determine 
acceptable and enforceable policies for passenger and crew use of portable electronic devices." The 
Terms of Reference were divided into two phases: a near-term PED technology assessment, and a longer- 
term technology assessment. An Internet website has been established to track meeting schedules, 
documentation, and terms of reference for the effort, which can be viewed at 
http://www.rtca.org/comm/sc202.asp . 



The EUROCAE working group and RTCA special committee efforts require openly available, high- 
confidence data upon which to base their analyses and recommendations. The goal of this NASA report 
is to provide suitable measurement processes, data and analysis that may be used by these committees, 
airlines and the FAA to establish a sound technical basis for allowing airplane operators and passengers 
freedom in using new wireless technologies in a manner that will not limit the safe operation of aircraft 
electronic systems. 

The NASA efforts described in this report, as well as those documented in [1], were accomplished 
with the support of the FAA Aircraft Certification Office and the NASA Aviation Safety Program. 
Additional path loss data were measured under a cooperative agreement with UAL and EWI. These 
measurements were conducted for various aircraft radio receivers on four Boeing B747-400 and six 
Boeing B737-200 aircraft. Utilizing receiver susceptibility threshold data from RTCA/DO-199 and GPS 
receiver performance specifications, interference safety margins were calculated and presented. The 
following subsections describe the objectives, the approach to measure spurious emissions, and the report 
organization. 

2.2 Objective 

The primary objectives of this work were to develop a radiated emission measurement process for 
WLAN devices and two-way FRS/GMRS radios, to conduct aircraft IPL measurement, and to provide 
interference risk assessment of WLAN devices and two-way radios to aircraft systems, including LOG, 
GS, VOR, and GPS. 

2.3 Approach 

Assessment of aircraft radio receiver interference is typically accomplished by addressing the three 
elements of the equation: 

A+ B> C, (Eq. 2.3-1) 

at any frequency in the aircraft radio navigation bands, where 

"A" is the maximum RF emission from the offending device in dBm, 

"5" is the maximum interference coupling factor in dB; "-B'\ in dB, is commonly referred to as the 
minimum IPL, 

"C" is the receiver's minimum in-band, on-channel interference threshold in dBm. 

If the minimum interference threshold, "C", is lower than the maximum interference signal level at the 
receiver's antenna port, "(^ + By\ there is a potential for interference. 

A primary focus of this effort was to measure the maximum RF emission, "A", from WLAN devices 
and two-way FRS/GMRS radios. In this report, the WLAN devices considered include IEEE 802.11a, 
IEEE 802.11b, and Bluetooth devices. Technically, Bluetooth is classified under Wireless Personal Area 
Network (WPAN) but it is grouped under WLAN in this report for simplicity. 

The secondary focus was to measure the minimum IPL, "-B", for a number of systems on several 
B747 and B737 aircraft. The new measured IPL data are summarized in this report and compared to 
other data previously available. 



Receiver interference thresholds "C" were not measured in this effort. Rather, test data from 
RTCA/DO-199 were used in evaluating interference risks to aircraft systems. DO- 199 provided receiver 
interference threshold data on a limited number of receivers for a few aircraft systems. Additional testing 
to include more receivers and more systems is highly desirable. Thorough measurement and analysis of 
receiver susceptibility thresholds requires having access to multiple aircraft receivers and in-depth 
knowledge of receiver operations and designs. Aircraft radio manufacturers are best equipped to address 
this issue. 

Sections 2.3.1 and 2.3.2 discuss in more detail the emission and path loss measurement approaches. 

2.3.1 Emission Measurements of WLAN Devices and Two-Way Radios 

To simplify the process and to reduce the number of emission measurements, aircraft radio bands that 
overlapped, or were near one another were grouped together, and emissions were measured across the 
entire combined band simultaneously. Five frequency groups, designated as measurement Band 1 to 
Band 5, covered all aircraft radio bands of interest. Table 2.3-1 correlates the measurement bands to 
aircraft radio frequencies. 

It is assumed that high emissions in any of Bands 1 through 5 would affect all aircraft systems 
operating in that band. As an example, high emissions in Band 1 are assumed to affect all LOC and VOR 
systems as a group. No effort was taken to distinguish whether the emissions were in LOC or VOR 
bands. 

Table 2.3-1: Emission Measurement Bands and Corresponding Aircraft Radio Bands. 



Measurement 

Band 
Designation 


Measurement 

Freq. Range 

(MHz) 


Aircraft Systems 
Covered 


Spectrum 
(MHz) 


Bandl 


105 - 120 


LOC 


108.1-111.95 


VOR 


108-117.95 


Band 2 


325 - 340 


GS 


328.6-335.4 


Band 3 


960-1250 


TCAS 


1090 


ATCRBS 


1030 


DME 


962-1213 


GPSL2 


1227.60 


GPSL5 


1176.45 


Band 4 


1565-1585 


GPS LI 


1575.42 + 2 


Bands 


5020-5100 


MLS 


5031-5090.7 



RCs were used to measure RF emissions from a device-under-test (DUT). Using this method, 
measured RF emissions resulted in "total radiated power" [4]. This method differs from the approach 
used in RTCA/DO-199, where the total radiated power was estimated from the electric field measured at 
a given distance from a DUT. Further details about conducting emission measurements in a RC are found 
in Section 3. 



The measurement process began with selecting host computer laptops/PDAs for the WLAN devices. 
This step ensured that spurious emissions from the intended WLAN devices were not masked by 



emissions from a noisy host laptop/PDA. This selection involved measuring emissions from eight 
different laptops and two PDAs operating in various modes. The laptops/PDAs with the lowest emissions 
in the idle and file transfer modes in a particular band were chosen for that band. The idle and the file 
transfer modes were typical laptop modes while emission measurements of the WLAN devices were 
being conducted. In addition, emission data of the laptops with all operating modes considered 
established an emission baseline for laptop computers that could be used onboard an aircraft. Emissions 
from intentional transmitters such as WLAN devices were compared against this baseline. For two-way 
FRS/GMRS radios, no similar host screening was needed since these devices can operate without a host. 

Emission measurements were conducted on five 802.11a, seven 802.11b and six Bluetooth WLAN 
devices. The WLAN devices were exercised through various modes, channels, and data rates during the 
emission measurement. Various filter combinations were used in the wireless AP antenna path to allow 
only the intended wireless signal to radiate for communication with the DUTs, and block spurious 
emissions from the APs. Additional filters were also used in the measurement path to prevent the 
wireless signals (from the wireless cards and the AP) from reaching the measuring instrument to cause 
overloading or intermodulation. 

Emissions were also measured on four matched pairs of FRS radios and three matched pairs of GMRS 
radios. Emissions from a matched pair were measured at the same time, with each radio in turn being in 
transmit, receive, and idle modes. Thus, a recorded measurement trace includes the maximum emissions 
from both radios in all three modes. The radios were also cycled through at least two frequency channels 
during each measurement. Again, filters were employed to prevent overloading of the measurement 
receiver. 

Further details are discussed in Section 3 of this report. 

2.3.2 Path Loss Measurements 

This effort supplemented the collection of previously available path loss data with measurements on 
four B747-400 and six B737-200 aircraft. In this effort, three separate measurement trips were made to 
an aircraft storage facility in Victorville, California to conduct IPL measurement on LOC, VOR, GS, 
VHF, TCAS, SatCom and GPS systems (if available). The results were plotted for different windows 
along each aircraft. The minimum path losses for the aircraft systems were summarized and shown along 
with other previously available data ([1], [2], [3], [5] and [21]), and the OYtvsill path loss statistics were 
computed for safety margin calculations. 

The measurement system included a spectrum analyzer and a tracking source with its frequency 
tracking (matching) the spectrum analyzer's frequency. The tracking source was used to deliver a known 
emission level to a matched and efficient transmit antenna simulating radiation from PEDs. The spectrum 
analyzer continuously swept and registered maximum emissions across the measurement band received 
by the aircraft antenna. The transmit antenna was pointed toward the windows or it was scanned along 
door seams. Past studies [5], and also the results of this study, confirmed that window and door locations 
provided the lowest IPL values. The difference in dB between the transmit antenna output power and 
power at the receiver's antenna cable port (measured by the spectrum analyzer) was the desired path loss 
value for that transmit antenna location. The transmit antenna was then moved to a different 
window/door/seat location and the process repeated until all desired aircraft locations 
(windows/doors/seats) were included. 



2.3.3 Safety Margin Calculations 

With device emission "A", path loss "-B" and interference threshold "C" known, the safety margin 
was calculated as: 

Safety Margin = C-(A-\-B) (Eq. 2.3-2) 

Results of the safety margin calculations are reported in Section 5. 

2.4 Report Organization 

Measurement of emissions from WLAN devices and two-way radios is described in Section 3. The 
method is described in 3.2, and a summary of the results is provided in Section 3.3. Section 3.4 
summarizes emission data from non-intentional transmitting laptops and PDAs. Section 3.5 compares 
results from all measurements reported in Sections 3.3 and 3.4. More detailed emission measurement 
results are shown in Appendix A for WLAN devices and two-way radios, and in Appendix B for laptops 
and PDAs. 

Section 4 describes IPL measurements and results for Boeing 747 and 737 aircraft, and a comparison 
with other previously available path loss data. Section 4.1 summarizes the aircraft measurements, with a 
detailed description in 4.1.1 and results in 4.1.2. Section 4.2 shows the minimum and the average IPL for 
each of the measured B737 and B747 aircraft, along with similar data previously reported. Section 4.3 
further condenses the data by showing the all-aircraft statistics of the minimum IPL. The lowest and the 
average values of the minimum IPL were used in the safety margin calculations in Section 5. 

Section 5 briefly summarizes the interference threshold data from RTCA/DO-199. In this section, 
interference safety margins for each aircraft system of interest are calculated and reported from the 
emission data, the IPL data, and the susceptibility thresholds. 

3 WLAN and Radio RF Emissions 
3.1 Wireless Overview 

IEEE 802.11a, IEEE 802.11b, and Bluetooth wireless network technologies and FRS/GMRS radios 
are described in this section. Table 3.1-1 lists types of devices used for this assessment with associated 
transmission frequency bands and operating parameters. In addition, the power used during radiated 
emission testing discussed in this report and the maximum permitted output powers, as specified by the 
corresponding standards or regulatory limits, are listed. 

3.1.1 IEEE 802.11a 

IEEE 802.11a is a very high-speed, high-bandwidth standard and a variant of the IEEE 802.11 
standard. It expands on the 802.11 network standard to define WLAN operating parameters, providing 
access to outside networks for wireless devices, including local intercommunication. The 802.11a 
standard requires that data rates of 6, 12, and 24 Mbits/s must be supported; however, maximum rates of 
54 Mbits/s are common. Each data rate uses a particular modulation technique to encode data. Higher 
data rates are achieved by employing advanced modulation techniques. Devices using 802.11a operate 
in the 5 GHz Unlicensed National Information Infrastructure Band (UNII). The bandwidth of 300 MHz is 



composed of three bands that legally operate in the US; the first band of 5.15 to 5.25 GHz uses 50 mW 
maximum power, the second band of 5.25 to 5.35 GHz uses 200 mW maximum power, and a third band 
of 5.725 to 5.825 GHz uses 800 mW maximum power [6]. The first and second bands contain eight non- 
overlapping 20 MHz channels. A typical application of 802.11a technology is a wireless NIC inserted 
into a laptop Personal Computer Memory Card Interface Adapter (PCMCIA) slot. The NIC converts the 
laptop, a non-intentional transmitter, to a wireless PED, capable of transmission and intercommunication 
with other wireless devices or APs. 

3.1.2 IEEE 802.11b 

The IEEE 802.11b standard provides location independent access to an outside network between 
wireless data devices, including intercommunication on a local scale. Primarily an extension of the 
802.1 1 standard, it defines additional operational parameters for high-rate data transfers on WLANs while 
maintaining 802.11 protocols. Devices using 802.11b operate in the 2.4 GHz band, which is divided into 
fourteen 22 MHz channels, eleven of which legally operate in the US. Adjacent channels partially 
overlap, except for three of the 14, which are completely non-overlapping. The 802.1 lb standard utilizes 
a Direct Sequence Spread Spectrum (DSSS) modulation mode, as defined by 802.11, and advanced 
coding techniques to achieve higher data rates of 5.5 Mbit/s and 11 Mbit/s. The coding techniques 
employ different modulation schemes at different data rates. The FCC allows a maximum output power 
of 1000 mW. However, if a power level greater than 100 mW is used, then power control must be 
provided by the system [6]. A distance range of 100 meters is typical, but ranges are dependent upon 
environmental obstacles and power. A typical application of 802.11b technology is a wireless NIC 
inserted into a laptop PCMCIA slot. As with 802.11a devices, a non-intentional transmitter is converted 
to an intentional transmitter that is capable of intercommunication with other wireless devices or APs. 

3.1.3 Bluetooth 

Bluetooth is a short-range radio technology with the capability to link together different wireless 
devices providing for data and limited voice communication. Bluetooth uses 79 channels separated by 1 
MHz each, from 2.4 to 2.48 GHz. The Bluetooth standard supports development of low cost and low 
power wireless devices. The specification allows for three power classes [7]. Power control is required 
for devices utilizing class one levels, and must be able to control and limit transmit power over 1 mW (0 
dBm) [7]. Power control is optional at levels under dBm, but may be employed in order to conserve 
power. Bluetooth units operate with a maximum data rate of 1 1 Mbps, and a power level up to 100 mW. 
The nominal distance between devices is 0.3 to 10 meters; however, greater distances are achieved with 
higher power. It uses Gaussian Frequency Shift Keying (GFSK) modulation combined with Frequency- 
Hopping Spread Spectrum (FHSS) techniques for data transmission [7]. A Bluetooth transmitter hops 
among 79 frequencies at a rate of 1600 hops per second. 

3.1.4 FRS/GMRS Radios 

FRS and GMRS radios are legal, modem, two-way communication devices in the US and Canada. 
These devices are more compact and more efficient than their walkie-talkie predecessors. They also have 
a longer communication range, less distortion, better signal reception, and more effective penetration of 
building structures. Both types of radios utilize 38 subcodes in each of the main channels, which enable 
users to achieve a semi-private conversation. A subcode is an interference filter allowing only the signals 
designated to a particular subcode on a channel to be heard by the users, blocking all other signals. 



Several users in fairly close proximity, fewer than two miles, are able to communicate with unlicensed 
FRS devices. However, if communication beyond 2 miles is needed, a licensed-GMRS device may be 
used. GMRS regulations do not permit superficial chatter between individuals on this service, unlike the 
FRS radio regulations. GMRS has a larger coverage area because of the higher output power and the 
ability to use repeaters in the coverage area. Table 3.1-1 provides a comparison of the two radios. 



Table 3.1-1: Wireless Technology Parameters 



Wireless 
Technology 


Frequency Band (GHz) 


Typical 

Data Rates 

(Mbps) 


Number 

of 
Channels 


Maximum 
Output Power 
per Std. / per 

Test (mW) 


Typical Range 


802.11a 


5.15-5.825 


6, 12, 24, 54 


12* 


800 / 40 & 200 


50 meters 


802.11b 


2.4-2.4835 


1,2,5.5,11 


11* 


1000/100 


24-100 meters 


Bluetooth 


2.4-2.4835 


1 


79' 


100 /<1** 


10-100 meters 


FRS Radio 


0.4625675-0.4677175 


NA 


14 


500 / 500 


2 miles 


GMRS Radio 


0.4625500-0.4677250 


NA 


23*** 


50000***7 2000 


5 miles 



* Legal channels in US 

** Less than 1 mW, varied by channel 

*** FCC Part 95 Subpart E 

' Utilizes FHSS over all channels 



3.2 Measurement Process 



This section incorporates discussions on preliminary investigations; emission testing conducted on 
laptop computers, PDAs, and a printer used as hosts for WLAN devices; and, device-focused tests 
conducted to measure radiated spurious emissions from w^ireless devices installed in a host. 
Determination of testing parameters is discussed, including procedures, RF filtering, host devices, WLAN 
devices, and test configurations. Several figures are included to illustrate the test environment, setup, and 
instrumentation. Tables are presented w^hich include information on measurement frequency bands, 
measurement bandw^idths, host and AP characterization, and WLAN configurations. A diagram of the 
test facility is presented with a discussion of NASA-LaRC High-Intensity Radiated Fields (HIRF) 
Laboratory RCs. The radiated emission test procedure is briefly discussed and includes calibration and 
emission measurement methods. Test matrices for WLAN devices and FRS and GMRS radios are 
presented to illustrate test modes. Finally, the data reduction process is discussed and the results are 
linked to data charts found in this report. 

The follow^ing sections describe the measurement process by presenting the measurement method 
used, the types of preliminary testing conducted, the specifics of the device-focused testing on WLAN 
devices, and the data reduction process. 

3.2.1 Measurement Method 

Overview 



The goal of this effort was to develop a process and representative data for measuring spurious 
radiated emissions in aircraft communication and navigation (com/nav) receiver bands from wireless 



devices meeting IEEE 802.11b, IEEE 802.11a, Bluetooth, FRS and GMRS radio standards. The 
measurement process for spurious radiated emissions incorporates RF measurement instrumentation, 
specialized data acquisition software, generation and application of calibration data, and the use of RCs 
[1]. Preliminary PED and WLAN device performance testing was conducted in both a Semi-Anechoic 
Chamber (SAC) and a RC; however, a RC was used for all emission testing in order to provide more 
comprehensive test results and to expedite the test process. Additional advantages of using the RC 
method are described in the next section. 

Test Facility Description 

The NASA-LaRC HIRE Laboratory has three separate RCs, as seen in Figure 3.2-1. This facility is 
capable of performing radiated susceptibility tests and emission tests using either one chamber at a time 
or in two or three chambers simultaneously. Using multiple chambers allows for distributed testing of 
systems, creating different electromagnetic environments in each chamber utilized. The National Institute 
of Standards and Technology (NIST) has characterized the field uniformity of the NASA-LaRC RCs; 
details regarding their performance are located in [14]. Characterization of the chambers by NIST 
indicates a high degree of electromagnetic field uniformity performance within the stated useable 
frequencies. A chamber's lowest useable frequency is determined by its construction and geometry, and a 
sufficient mode density within the chamber to provide a uniform electromagnetic environment [13]. 



Chamber A 
14.33m X 7.01m X 2.90m 







Door 





"I 1 r 



Chamber B 
7.01m X 3.96m X 2.90m 



Door 



HI 



HI 




H h- 



Amplifier Room 
5.49m X 7.32m X 3.05m 



Control Room 

5.49m X 7.32m X 3.05m 



Door |1 



2.72m X 2.13m X 2.90m 

Figure 3.2-1: Layout and dimensions of the HIRF Laboratory at NASA LaRC. 



The lowest useable frequency for Chamber A is approximately 100 MHz with +/-2 dB variation [14], 
and it accommodates test measurement frequency Bands 1 and 2 (Table 2.3-1). The lowest useable 
frequency for Chamber C is approximately 300 MHz with +/-2 dB variation, and it accommodates 
measurement frequency Bands 3, 4, and 5. Chamber A has the capability to test all the emission 
measurement bands. However, intermittent low-level noise interference was observed in the higher 



bands, and Chamber C was used instead. Chamber B, which was unavailable at the time, could also be 
used in the future with its 150 MHz lowest usable frequency. 

Radiated emission measurements in RCs produce results in terms of radiated power, which is 
preferred, rather than electric fields as in a SAC. Radiated emissions in term of power can be applied 
directly into Eq. 2.3-1 for interference risk assessment. Compared with the SAC method, the advantages 
of the RC method also include repeatability and speed when a large number of aspect angles in the SAC 
are considered. The RC method does not suffer from measurement uncertainty caused by multipath 
effects. However, establishing and maintaining connectivity with a wireless DUT can be much more 
difficult in a RC than in a SAC due to severe multipath interference. In addition. Section 3.2.2 provides 
more details on connectivity issues associated with WLAN devices in a reverberation chamber. 

The RC method, however, may not be appropriate for measuring emission signals with very short 
pulse durations [15]. Due to high chamber quality factor, the chamber time-constant should not be greater 
than 0.4 of the pulse-width of the modulated signal. This requirement ensures that once a pulsed signal is 
turned on, the field environment in the chamber reaches (near) steady-state level before the pulse is turned 
off. RF absorber can be added to the chamber to lower the time-constant; however, emission signal 
characteristics must be known in advance for all DUTs in all measurement bands. In addition, 
measurement sensitivity would be reduced. A method for measuring chamber quality factor and time- 
constant is described in [15]. Absorber was not added in this study. 

For the RCs used, the chamber time-constants vary with frequency, and are about 0.5 to 2 
microseconds in the measurement bands of interest. It is assumed that most RF emission signals measured 
in this effort are continuous-wave (CW), or pulse modulated signals of five microseconds (= 2 
microseconds / 0.4) or longer. 



Description of Measurement Method 

Figure 3.2-2 shows the emission test setup in an RC. Tests conducted in RCs rely on several different 
methods to produce a statistically uniform and isotropic electromagnetic environment (field statistics 
measured over one stirrer revolution are isotropic and spatially uniform). Two of these methods are 
mode-stirred and mode-tuned [13]. Stirrers with reflective surfaces are rotated continuously during 
mode-stirring, or stepped at equal intervals for a complete rotation during mode-tuning. For 
measurements in this report, the mode-stirred method was adopted due to ease of setup, implementation, 
and significant speed improvements over the mode-tuned method. While the mode-tuned method can be 
more accurate in immunity testing applications (especially for DUTs with slow response time), the mode- 
stirred method is superior for most emission measurements due to speed. With a spectrum analyzer for 
measuring receive power, the emission measurement system can respond fast enough to the changing 
fields caused by the continuously rotated stirrers. Settling-time delays for stirrer stepping in mode-tuned 
operations are eliminated, resulting in significant speed improvements. In addition, combining mode- 
stirred operations with continuous frequency sweeping can further expedite the measurements. 

Measurement uncertainty levels can be lowered by selecting the number of measurement points in a 
stirrer revolution approximately equal to the number of calibration points. In addition, the number of 
measurements during one stirrer revolution should be as large as possible within constraints of instrument 
capabilities and test time to reduce uncertainties. Using the mode-stirred method, several thousand 
measurements per stirrer revolution are easily achievable with a spectrum analyzer. On the other hand, the 
mode-tuned method with the number of measurements exceeding 100 per stirrer revolution is typically 



10 



considered impractical due to excessive test time. The mode-stirred method's short calibration times also 
allow for frequent chamber calibrations to correct for DUT operator changes during long test times. 



Control and 
Data Acquisition 



PC Test r=r 
Controller | | 



HP8561E 
Spectrum 
Analyzer 



IEEE488 
Bus 

HP85644A 

Tracking 

Source 



Stirrer 
Controller 



□ 




Filter & 
Preamp 



Loc. Oscillator 
Connection 




Stirrer 



Lines to 
Stirrers 



Bandpass 
Filter 



t; 



Capped Port 



^X3 



Access Point 




Ethernet 
Cable 



Figure 3.2-2: RC and WLAN emission test configuration. 



Emission measurements using the mode-stirred method typically involve [15]: 1) Empty chamber 
insertion loss measurement; 2) Measurement of chamber loading, caused by the presence of a test 
operator and test equipment inside the chamber; and 3) Measurement of maximum receive power over a 
paddle rotation of the stirrer with the DUT powered on in various test modes. The total radiated power 
within the measurement resolution bandwidth can be calculated using [15, appendix E]: 



TotRad 



= (P. 



MaxRec 



^r]T,)l{CLF^IL\ 



(Eq. 3.2-1) 



where 



^TotRad 

p 

^ MaxRec 



total radiated power within the measurement resolution bandwidth, 
maximum received power measured over one complete paddle rotation. 



11 



CLF = chamber loading factor, or the additional loading effects caused by the presence 

of objects or operators in the test chamber, 

tJtx = efficiency factor of the transmit antenna used in chamber calibration and 

assumed to be unity for the antennas used, 

IL = empty chamber insertion loss, pre-determined during chamber calibration. 

IL is measured during chamber calibration, and is defined as the ratio of the maximum receive power 
and the transmitted power in a stirrer revolution [15: appendix B]: 



IL — iMaxRec^ P Input ? (ECJ. 3.2-2) 

where PmaxRec and P input are the maximum received power and the transmit power at the antennas, 
respectively. 

In [15], /L is first measured and averaged over multiple locations for improved uncertainties. CLF is 
then measured once (one location) when test objects or personnel are introduced into the test chamber. 
Correction for CLF is applied only when the values exceed a given threshold (3 dB is specified in [15]). 
In this effort, a simplified one-step process was used instead: (CLF^IL) combination was measured 
together. This one-step process requires that the DUTs and DUT operator be present in the chamber 
during calibration. The chamber loading factor measurement is no longer needed, eliminating 
uncertainties about whether a correction for CLF should be applied. To reduce the burden on DUT 
operators, {CLFHL) was measured at one location rather than averaged over multiple locations. The 
effect is an acceptable small increase in uncertainty (of about two dB or less depending on chamber field 
uniformity and frequency). 

In an actual setup, it is often convenient to include transmit and receive path losses in the chamber 
calibration measurements. These path losses account for the presence of test cables, in-line amplifiers, 
attenuators and filters for various purposes. Transmit path losses are associated with components 
connecting the source output and the transmit antenna, whereas receive path losses are associated with 
components connecting the receive antenna and the spectrum analyzer input. As result, chamber 
calibration factor {CF), in dB, is introduced: 

Cr = ( Pxmit(dBm) " PsAMeas(dBm) ) 

~ ^C/zmZ?r(^fi) "*" L^Q^Cable(dB) "*" LxmitCable{dB) ' v^^* 3.2-3) 

where 



CF 


chamber Calibration Factor (dB), 


Lchmbr(dB) ~ 


chamber loss (dB), or 


= 


-lOlog.oiCLF^IL), 


WecCable(dB) ~ 


receive cable loss (dB), 


LxmitCable(dB) ~ 


transmit cable loss (dB), 



12 



^sAMeas(dBm) ~ maximum receive power measured at the spectrum analyzer (dBm) over one 

stirrer revolution, 
Pxmit(dBm) - power transmitted from source (dBm). 

Passive losses (not to include amplifier gains) are defined to be positive in dB. The total radiated 
power in dBm can be computed using: 

^TotRad(dBm) ~ ^SAMeas(dBm) ~ ^XmitCable(dB) "*" ^^ * v^^* -^-^"4) 

As shown in Figure 3.2-2, measurement instrumentation included a spectrum analyzer, a tracking 
source (frequency-coupled with the spectrum analyzer), a computer, a stirrer controller, transmit and 
receive antennas, RF filters, pre-amplifiers, and an IEEE-488 bus. The measurement procedure begins by 
performing a transmit path loss calibration. Transmit path losses are measured at each frequency by 
injecting a known power from the tracking source through the cable to the antenna connector and using a 
spectrum analyzer to measure the loss. Next, a chamber calibration is performed. A known level of 
power is delivered from the source into the chamber through the transmit antenna while the stirrer(s) are 
continuously rotated at a predetermined rate. The spectrum analyzer is used to record the maximum 
power coupled into the receive antenna (and the receive path) while performing synchronized frequency 
sweeps with the tracking source across the measurement bands. Eq. 3.2-3 is applied to determine the CF 
[1,12]. 

The source is then removed, and the transmit path connection terminated, to avoid leakage from the 
source into the chamber. With the DUT powered off, a radiated emission measurement is conducted to 
measure noise floor levels in each band. Then the DUT is powered on and a radiated emission 
measurement performed at each frequency with the DUT placed in each test mode. During the emission 
measurements, the spectrum analyzer is put on maximum hold mode while continuously sweeping over 
the measurement frequency band. The control software applies the equation Eq. 3.2-4 to normalize the 
measured power with the calibration data [1]. 

Figure 3.2-2 shows the position of a host and WLAN device in the center of the chamber, represented 
by a laptop computer on a foam block test stand. The AP antenna is also located on the same test stand. 
Utilizing the mode-stirred method, the two stirrers located in the corners of the chamber were 
continuously rotated at 5 rpm during chamber calibrations and emissions testing. Also illustrated is the 
control and data acquisition system. Note the line labeled Local Oscillator Connection. This line actually 
represents several connections between the tracking source and spectrum analyzer that ensure frequency 
synchronization. RF filters and a preamplifier are indicated in the receive path. The wireless network is 
illustrated outside the chamber, and includes an AP, a router, a wired laptop, and a bandpass filter inline 
with the AP antenna. A 20 dB attenuator is located inside the chamber at the AP antenna. This attenuator 
was used to improve wireless network communications by reducing signal overload caused by close 
proximity of the AP antenna and wireless card. The AP antenna and the wireless card were placed close 
to each other to overcome multipath interference. The AP antenna port that was not used was capped 
with a 50-ohm termination to prevent signals outside the chamber from coupling in through the AP. 



13 



3.2.2 Preliminary Testing 

Overview 

Before radiated spurious emission measurements began, several preliminary and exploratory tests 
were performed. The requirements for filtering were analyzed and specific parameters were determined 
for selecting filters and preamplifiers. In addition, emission tests were conducted on PEDs in order to 
establish host baselines, and APs and WLAN devices were characterized and selected. 

During preliminary and emission testing of WLAN devices, two tests were performed, ping storm and 
duplex file transfer. Ping was used to probe the target, a WLAN device, and determine if the network was 
functioning correctly. A network ping sends a null packet, which is a very small packet of 8 bytes, plus 
standard Transmission Control Protocol/ Internet Protocol (TCP/IP) overhead over the network. This 
packet contains enough information to locate a particular receiving device or client using its IP address. 
The receiving device will then send a minimal response. The round-trip usually takes only milliseconds 
and indicates that the devices are communicating and that the network is operating correctly. A ping 
storm occurs when a ping is sent continuously over the network. Duplex file transfers between laptops 
were also conducted. A data file from a wired laptop was sent to a WLAN laptop and vice versa, 
simultaneously. These types of tests were performed during AP characterization and radiated emissions 
measurement testing. 

In addition, emissions tests were conducted on eight laptop computers and two PDAs in the five 
measurement frequency bands using several different operating modes. The resulting emissions data 
were analyzed and compared to determine from measured emission levels which laptop computers to use 
as hosts for the WLAN devices during emissions tests. 

Determination of Required Filtering 

Tests were performed in a RC using an HP85644A sweeping source to determine if representative 
device emissions caused intermodulation or false spurious emissions within the measurement system in 
each measurement frequency band. These tests were conducted with required preamplifiers in place, and 
band-specific filters to avoid overdriving the preamplifiers. Figure 3.2-2 illustrates the receive path used 
during calibration and emission testing with filters and preamplifier in place. Tables 3.2-1, 3.2-2, and 3.2- 
3 give the designated RC, preamplifier, receive antennas, spectrum analyzer settings, and filters used 
during calibration and emission measurements for each threat type and frequency band. 



14 



Table 3.2-1: FRS/GMRS Threat Source (440 - 470 MHz) 



Freq. 
Band 


Cbr. 


Pre- Amplifier 
Used 


Receive Antenna 


Spectrum 
Analyzer Settings 


Specified filter before 
Pre- Amplifier 


1 


A 


Miteq AU-1291-N- 
1 103-1 179-WP, 
60 dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 8IL40-336/U468 

Lowpass 

Cutoff Freq. 336 MHz 


2 


A 


Miteq AU-1291-N- 
1103-1 179-WP, 
60 dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 8IL40-336/U468 

Lowpass 

Cutoff Freq. 336 MHz 


3 


C 


HP83017A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= lOOkHz 
Atten .= OdB 


K&L 4IH30-926/U1600 (2) 

Highpass 

Cutoff Freq. 926 MHz 


4 


C 


Antenna Integrated, 
55dB 


Impulse 2104NW 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 4IH30-926/U1600 (2) 

Highpass 

Cutoff Freq. 926 MHz 


5 


c 


HP83017A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= 30kHz 
Atten.= OdB 


K&L 9FV30-5061/X60 

Bandpass 

5031 -5091 MHz 



Table 3.2-2: IEEE802.11b, Bluetooth Threat Source (2400 - 2500 MHz) 



Freq. 
Band 


Cbr. 


Pre- Amplifier 
Used 


Receive Antenna 


Spectrum 
Analyzer Settings 


Specified filter before Pre- 
Amplifier 


1 


A 


Miteq AU-1291-N- 
1103-1 179-WP, 
60 dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten.= OdB 


K&L 4IL30-600/U2497 

Lowpass 

Cutoff Freq. 600 MHz 


2 


A 


Miteq AU-1291-N- 
1103-1 179-WP, 
60 dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten.= OdB 


K&L 4IL30-600/U2497 

Lowpass 

Cutoff Freq. 600 MHz 


3 


C 


HP 830 17 A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= lOOkHz 
Atten.= OdB 


K&L 6IL30-1600/U2497 

Lowpass 

Cutoff Freq. 1600 MHz 


4 


C 


Antenna Integrated, 
55dB 


Impulse 2 104NW 


HP 8561E 
RBW= lOkHz 
Atten.= OdB 


K&L 61L30-1600/U2497 

Lowpass 

Cutoff Freq. 1600 MHz 


5 


C 


HP83017A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= 30kHz 
Atten.= OdB 


K&L4FV30-5050/X100 
Bandpass 
5000-5100 MHz 



15 







Table 3.2-3 


: IEEE802.1 la Threat Source (5150 - 5825 MHz) 


Freq. 
Band 


Cbr. 


Pre- Amplifier 
Used 


Receive Antenna 


Spectrum 
Analyzer Settings 


Specified filter before Pre- 
Amplifier? 


1 


A 


Miteq AU-1291-N- 
1 103-1 179-WP, 
60dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 6IL30-1600/U2497 

Lowpass 

Cutoff Freq. 1600 MHz 


2 


A 


Miteq AU-1291-N- 
1103-1 179-WP, 
60 dB; 
HP8491B 
Attenuator, 10 dB 


AHSAS-200/514 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 6IL30-1600/U2497 

Lowpass 

Cutoff Freq. 1600 MHz 


3 


C 


HP 830 l&A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= lOOkHz 
Atten .= OdB 


K&L 6L250-4000/T 1800(2) 

Lowpass 

Cutoff Freq. 4000 MHz 


4 


C 


Antenna Integrated, 
55dB 


Impulse 2104NW 


HP 8561E 
RBW= lOkHz 
Atten .= OdB 


K&L 6L250-4000/T 1800 

Lowpass 

Cutoff Freq. 4000 MHz 


5 


c 


HP83017A, 40dB 


AHSAS-200/571 


HP 8561E 
RBW= 30kHz 
Atten.= OdB 


K&L 9FV30-5061/X60 

Bandpass 

5031 -5091 MHz 



Host Device Baseline 

WLAN devices come in two different forms: 1) a removable PC card; or 2) integrated into an 
electronic system, which enables its host device to communicate with a mobile or fixed network using 
assigned radio frequencies. WLAN transmitters do not function independently and must be installed in a 
host device. A host is a PED that a user chooses to be mobile and linked to other PEDs in order to 
exchange information. A baseline of spurious radiated emissions for each possible host was measured in 
the five measurement frequency bands. This phase of testing determined the "quietest", or lowest peak 
radiated emission power for each PED, and was used to determine hosts for WLAN device testing. 
Various laptop computers were used as test objects. Table 3.2-4 shows the laptops, PDAs, and a mobile 
printer considered. 

Laptop Computers 

Spurious radiated emissions were recorded for all five measurement frequency bands with each of the 
eight laptops operating in five modes. Modes are processing tasks that may be performed by a laptop 
while in use. Radiated emissions from the modes (idle, flowerbox Screensaver, file transfer, CD, and 
DVD) were measured separately and then plotted with each other to achieve a maximum radiated peak 
envelope of the laptop, which is discussed further in Section 3.4. The flowerbox Screensaver was selected 
to be a large, smooth, checkerboard cube pattern that spins and blooms at maximum complexity. The file 
transfer mode transfers a file from the hard drive to the PCMCIA slot mounted microdrive. Idle mode 
testing is conducted as a normal desktop screen is displayed. In order to exercise the video and audio 
cards, a CD and DVD were played. Appendix B contains results of the plotted data. 



16 



In order to determine the emissions from the WLAN devices, laptop emissions were independently 
measured to create a baseline. Combining idle and file transfer modes created a baseline, which is 
directly compared with the DUT (WLAN device paired with its host) idle, ping storm, and file transfer 
values across the measurement frequency band. This comparison reveals what effects the WLAN device 
adds to the host emission levels. The baseline was used to determine the "quietest" host in each of the 
measurement bands. LAP4 and LAP6 were chosen as hosts since they had the lowest peak radiated 
emission power baseline levels in some measurement frequency bands. LAP4 is the host for WLANs 
tested in RC A, which was configured to test Bands 1 and 2. LAP6 was the host for WLANs tested in RC 
C, which was configured to test Bands 3, 4, and 5. Figure 3.2-3 illustrates the configuration for a 
chamber with a tracking source (for calibration), a spectrum analyzer, transmit and receive antennas (log 
periodic, GPS, and horn), a laptop computer, and an operator. 

PDA and Printer 

A PDA baseline consisted of the idle and file transfer modes. File transfer in this case was performing 
a backup operation to a secure digital or compact flash card. 

The battery powered printer was used as a host for a BlueTooth - USB printer adapter. The printer's 
baseline solely consisted of the idle mode with the unit powered on. Peak radiated emission power levels 
from these hosts are located in Appendix B. Host baselines are compared with the DUT emission 
measurements to determine how the WLAN affects the host emission levels. 

Table 3.2-4: Laptop, PDA, and Mobile Printer Models 



Host 
Designation 


Manufacturer 


Model 


LAPl 


Dell 


Latitude C640 


LAP2 


HP 


Pavilion n6395 


LAPS 


Sony Vaio & Dock 


PCG-641R 
PCGA-DSM51 


LAP4 


Dell 


Latitude C800 


LAPS 


Fujitsu 


Lifebook 


LAP6 


Panasonic 


Toughbook CF-47 


LAP7 


Fujitsu 


Lifebook CP109733 


LAP8 


Gateway 


450SX4 


PDAl 


Palm 


m515 


PDA2 


Toshiba 


e740 


PRN 


Hewlett Packard 


DeskJet 350 



17 



Reverberation Chamber A 





Xmit Antenna 



GPIB Cable 





Receive Antenna 



I 



Figure 3.2-3: Setup for host baseline in RC A 



Test Set and Wireless Device Characterization and Selection 

Prior to conducting radiated emission testing, WLAN APs and a Bluetooth test set were characterized 
to determine operating limitations, performance, and noise levels. Two 802.11a APs, two 802.11b APs, 
and one Bluetooth test set were evaluated. The Bluetooth test set and APs, also utilized as test sets, 
served as DUT controllers for setting WLAN parameters such as data rates, channels, and power. In 
addition, the test sets and wireless device combinations were evaluated. 

802.11a and 802.11b Data Rate and Channel Control 

The ability of APs and WLAN devices to control data rates, channels, and power was tested and 
verified. Various AP and wireless PC card combinations were tested to determine interoperability and 
performance. WLANs were set up and operated in appropriate configurations (Figure 3.2-4) in a SAC 
and a RC. A network configuration consisted of an AP, acting as a bridge between devices or clients, and 
a wireless base station connected to a router that functioned as server for IP addresses; a wired laptop, 
connected to the router; and a laptop with a wireless NIC installed in the computers PCMCIA slot. Each 
AP was configured as required by using TCP/IP network links and a browser on the wired laptop that 
interfaced with AP software to setup and control operational parameters. Another laptop with a wireless 
PC card inserted and interface software installed was used to communicate with an AP through the 
wireless network. WLAN cards were tested in infrastructure mode only, one at a time. 

Figure 3.2-4 shows a diagram of the operational evaluation setup of the WLAN in a RC. Tests were 
conducted to determine the data rates and channels to be used during emissions testing. For testing the 
capabilities and performance of APs and PC cards, a ping storm was initiated from the AP control wired 



18 



laptop to the WLAN laptop (Figure 3.2-4) while various data rates and channels were applied. Duplex 
file transfers between laptops were also conducted. A data file from the wired laptop was sent to the 
WLAN laptop with PC card and vise versa, simultaneously. Again, various data rates and channels were 
tested while transferring files. 



Wired Laptop 



Router Access Point 



AP Antenna 



Laptop w/PC Card 




Foam Block 



Foam Block 



Figure 3.2-4: Preliminary testing WLAN configuration. 

Figure 3.2-5 contains pictures of the preliminary testing setup in a RC. Note that a log periodic 
receive antenna and a spectrum analyzer were used to monitor the spurious signals in the measurement 
bands. The wired and wireless laptops are shown, as well as the AP with attached antennas and network 
router. 





Figure 3.2-5: Preliminary AP and WLAN device evaluation testing in RC. 

Continuous operation in a RC was more difficult to maintain than in a SAC due to multipath 
propagation conditions. Multipath loss occurs as the RF signal bounces off the chamber walls and 
rotating paddles within the chamber enroute from the AP antenna to the WLAN device. The rotating 
paddles are the greatest contributor to this loss. As a result, the signal can take more than one path. 



19 



arriving at the WLAN device as multiple or attenuated signals. WLAN performance was significantly 
impacted by these losses. 802.1 la device communications were more difficult to maintain in an RC than 
were 802.11b device communications. In these cases, the AP antenna was placed at a distance 
approximately one to three inches from the PC WLAN card in order to establish the network connection. 
Reducing the AP antenna and card distance did improve connection stability by reducing the effect of 
multipath signals. During emission testing, a 20dB attenuator was added at the AP antenna to prevent the 
WLAN card and AP antenna from overpowering each other when the two were in close proximity. 

The more robust APs and cards were able to operate continuously with fewer dropouts and quicker 
recovery. Many of the faster data rates were difficult to sustain in this multipath environment. The 
selection of data rates during emission testing was determined largely by the capability of the AP/card 
combination to maintain association and communication and to perform in a robust manner. Data rates 
were selected based on the AP operability at each rate, and the desire to test as many data rates and 
modulation schemes as possible. 

Preliminary operational testing of APs and PC cards was used to determine channel selections. 
Changing channels moves the transmission signal from one frequency to another within the larger 
operational frequency band for a particular type of device. The 802.11a WLAN devices used during 
testing were limited to the first two operational bands (5.15 to 5.25 GHz and 5.25 to 5.35 GHz). The 
availability of certain channels was further limited by equipment selected. 

802.11a and 802.11b WLAN Operational Evaluation 

APs were tested to determine their operational capability in a RC environment by verifying 
transmission signals and identifying any spurious signal emissions. Tests were conducted to determine if 
test sets emitted signals through their antennas and produced noise in the five measurement bands. 
Radiated emissions were measured in a RC with APs active, but no PC cards or other WLAN devices 
present. No significant spurious signals were noted during the preliminary tests of the APs; however, 
bandpass filters were added inline between the APs and antennas during emissions testing to ensure that 
no out-of-band emissions were radiated into the chamber. 

Results of 802.11a and 802.11b Preliminary Testing 

All data rates and channels allowed by the APs, test set, and cards were exercised during preliminary 
operational testing. Among various AP and card combinations, there were configuration and operational 
variations. While some WLAN cards automatically configure to the associated AP data rate and channel, 
others do not, and can be set independently. Communication and setup interfaces varied in ease-of-use 
and capability. Among the various devices tested, some had a greater number of available data rates, 
channels, and modes. The ability to control power levels proved to be very limited; therefore, PC cards 
were configured and maintained at maximum power levels. Power level maximums were 200 mW for 
802.1 la devices and 100 mW for 802.1 lb devices. 

Ultimately, two APs, one for 802.11a tests and one for 802.11b tests, were selected based on ease-of- 
use, overall capability, and robust behavior. The selected APs each had removable antennas, adjustable 
power settings, and short delays during configuration changes. Limiting test conditions were largely 
associated with PC cards. For instance, out of eight 802.11a PC cards, two were not capable of turbo 
mode, thereby, limiting data rates and channels. Certain brands of PC cards were unable to maintain 
higher data rates reliably and produced numerous dropouts and disassociations from the AP. Except for 
duplicates, all PC cards tested during the preliminary stage were used during emissions testing. A total of 



20 



five 802.11a PC cards and six 802.11b PC cards were selected for emissions testing. The 802.11a 
selected data rates and associated modulation schemes are listed in Table 3.2-5, and selected channels and 
maximum output power are listed in Table 3.2-6. The 802.11a AP chosen for use during emissions 
testing had a high-speed or turbo mode capabiHty that allowed for three additional channels. In addition 
to the normal channels shown in Table 3.2-6, channels 42, 50, and 58 were also used when operating in 
turbo mode. The 802.1 lb selected data rates and associated modulation schemes are listed in Table 3.2-7, 
and selected channels and maximum output power are listed in Table 3.2-8. Table 3.2-8 shows that the 
channel numbers chosen for 803.11b emissions testing were 1, 6, and 11, as these channels are non- 
overlapping in frequency bandwidth. . 



Table 3.2-5: 802.11a Selected Data Rates 



Data Rate (Mbps) 


Modulation** 


6 


BPSK 


12 


QPSK 


24 


16-QAM 


36* 


16-QAM 



* Available in turbo mode. 

**BPSK - Binary Phased Shift Keying, QPSK - Quadrature Phased Shift Keying, 16-QAM - 16 bit Quadrature 

Amplitude Modulation 



Table 3.2-6: 802.11a Selected Channels. 



Channel Numbers 


Frequency (MHz) 


Maximum Output 
Power 


36 


5180 


40 mW 


42* 


- 


40 mW 


48 


5240 


40 mW 


50* 


- 


- 


58* 


- 


200 mW 


64 


5320 


200 mW 



* Turbo Mode Channels 



Table 3.2-7 802.1 lb Selected Data Rates 



Data Rates (Mbps) 


Modulation* 


1 


BPSK 


2 


QPSK 


11 


QPSK 



*BPSK - Binary Phased Shift Keying, QPSK - Quadrature Phased Shift Keying 



Table 3.2-8: 802. 1 lb Selected Channels 



Channel Numbers 


Frequency (MHz) 


Maximum Output 
Power 


1 


2412 


100 mW 


6 


2437 


100 mW 


11 


2462 


100 mW 



21 



Bluetooth Test Set Operational Evaluation and Characterization 

An evaluation of an Agilent Technologies E1852B Bluetooth Test Set was conducted to determine if 
the operational modes of COTS Bluetooth devices could be controlled by the test set. A laptop installed 
with Agilent's Bluetooth test set interface software was used to send inquire and page commands in 
normal mode. A communication link between the test set and a Bluetooth device occurs when the test set 
detects any Bluetooth device in its coverage area by using device address inquiries. The Bluetooth device 
address is selected to establish a connection and to implement a normal mode page communication link. 
A normal mode connection sends null packets with a header over the network to the Bluetooth device, 
which returns a reply to the Bluetooth test set. Once a connection is made, it will remain in place until the 
operator releases it. All off-the-shelf Bluetooth devices tested were unable to establish a connection 
through the test mode page because manufacturers remove this feature before devices reach production 
phase. Test mode allows a payload to be attached with the header to simulate a file transfer. 

An investigation of noise floor signal and response from the Bluetooth test set was conducted in the 
reverberation and semi-anechoic chambers. Figure 3.2-6 illustrates the setup used in the RC and the 
SAC. The Bluetooth test set was able to inquire a Bluetooth device inside the chamber and remain 
connected after a page. Since multipath phenomenon exists inside RCs, there is a potential for signals to 
couple through the Bluetooth antenna to the test set causing interference. At this point, a hardware reset 
was implemented, which returned the test set to normal. The Bluetooth test set SAC investigation 
verified that multipath signals caused interference on the test set in the RC. The test set functioned 
properly in the SAC. Observations of the Bluetooth test set transmission signal into the RC or SAC 
resulted in no significant spurious signals displayed on the spectrum analyzer. 



Bluetooth 
Controller 



Tracking Source 



, IZZIl 3 



Spectrum 
Analyzer 



/T 






}\ 




O 


booc 


J 



L 



Bluetooth 

Test Set 



Stirrer 




Transmit Antenna 



DUT 

(Host + WLAN 
Device) 




V^ 



/ \ Receive 
/ \ Antenna 




Figure 3.2-6: Bluetooth test set evaluation configuration in RC. 



22 



3.2.3 Device-Focused Testing 

Overview 

Measurements of spurious radiated emissions were conducted on 802.11a, 802.11b, and Bluetooth 
WLAN devices, and FRS and GMRS radios in five measurement frequency bands. Devices tested 
include five 802.11a PC cards, six 802.11b PC cards, two PDA-based 802.11b and Bluetooth cards, and 
six Bluetooth devices. In addition, fourteen FRS/GMRS radios were paired and tested. Host baseline test 
results were used to select laptops for use during emission testing. 

Several industry standards were consulted to determine and justify measurement parameters. This 
section includes tables listing measurement parameters, such as test measurement bands, resolution 
bandwidths, sweep times, dwell times, and noise floor estimates. An analysis was conducted to determine 
minimum test times or dwell times required in a RC in order to ensure adequate measurement sampling. 
Instrument and preampHfier noise measurements were conducted and combined with other losses and 
gains to determine the minimum measurement sensitivity for each of the five measurement bands. 

The test procedure is further detailed in this section and applied for testing wireless devices. 
Examples of test matrices for each type of device tested are presented in order to describe the components 
of a typical emission test. 

Included in this section are the following topics that describe the device-focused testing of WLAN 
devices: the selection and use of test instrumentation parameters; an analysis of measurement sensitivity; 
a description of the WLAN devices and radios selected for testing; radiated emission measurement test 
details; examples of test matrices; multipath interference issues; and, finally, the data reduction process. 

Frequency Bands, Measurement Bandwidth and Scan Time 

Spurious radiated emissions from PEDs may be caused by internal oscillators, clocks, data buses, 
motors and any other circuitry that generates currents and voltages in the device that vary over time. By 
their very nature, spurious radiated emissions from randomly selected PEDs have widely varying time, 
frequency and bandwidth characteristics. The specific time, frequency and bandwidth characteristics of a 
particular PED emitter are vitally important in determining the exact potential or that emitter to cause 
harmful EMI to a particular victim system. Unfortunately, it becomes prohibitively difficult to measure 
every possible signal characteristic that may be generated by every PED. Because of this difficulty, 
standard procedures for measuring spurious radiated emissions from electronic equipment must make 
compromises in terms of dwell time and measurement bandwidth, over different regions of the RF 
spectrum. Narrow measurement bandwidths result in improved sensitivity and frequency resolution, but 
carry a penalty in longer measurement times (slower sweeps or more frequency samples required over a 
frequency band), and will underestimate the amplitude of spurious signals with bandwidth larger than the 
measurement bandwidth. For certain complex or multifunction PEDs, spurious radiated emissions may 
be intermittent or present only during specific operating modes. In this case, the measurement time (or 
dwell time) at a particular frequency needs to be adequate to provide confidence that the maximum 
emission amplitude has been measured. 

Test parameters used in spurious radiated emission testing for this report, such as frequency bands, 
measurement bandwidth, and scan time were based upon those used in [1], with the addition of the MLS 
frequency band. The RTCA/DO-233 procedure [3] recommended that measuring-equipment bandwidths 
be chosen so ambient levels are at least 6 dB below emission limits, and it specified minimum 



23 



measurement times based upon MIL-STD-462D [8]. DO-233 reconmiended a single, slow sweep over 
each frequency band, to meet the required measurement time. As a spectrum analyzer operates, it 
displays the amplitude at each frequency during a sweep. Because the RC boundary condition changes 
with stirrer position, multiple measurement samples are required at different stirrer positions in order to 
find the maximum coupling amplitude. More samples are required by RTCA/DO-160D at lower 
frequencies to provide confidence that the peak amplitude was accurately measured. However, care must 
be taken to ensure that peaks are not missed at higher frequencies as well. To reduce test time for the 
mode-stirred measurements, multiple short sweeps were used instead of a single long sweep, while 
continuously rotating the chamber stirrers. 

There are several references applicable to measurement bandwidths. Some of these references are 
listed in Table 3.2-9. RTCA/DO-160D is directly applicable to assess the potential for spurious radiated 
emissions to interfere with commercial aircraft communication/navigation systems, and specifies that 
bandwidths of 10 kHz ". . .shall be used in the notches with no correction factor being applied". (Notches 
apply to aircraft communication/navigation receive bands, including GPS and MLS.) The purpose for the 
reduced bandwidth is to improve measurement sensitivity. This is reasonable for VOR, LOG and GS 
(Bands 1 and 2) because the channel bandwidths are no greater than 10 kHz. A resolution bandwidth of 
10 kHz is selected for GPS (Band 4), in keeping with the RTCA/DO-160D recommendation, while 
allowing reasonably short-duration sweep times. A resolution bandwidth of 10 kHz for the 
DME/ATCRBS/TCAS frequency band (Band 3) results in excessively long sweep times; therefore, a 
resolution bandwidth of 100 kHz is selected for Band 3. This bandwidth is in line with standards that 
recommend a 100 kHz measurement bandwidth below 1000 MHz and allows for a reasonably short- 
duration sweep time. The selected parameters for frequency bands, measurement bandwidth, and scan 
times are shown in Table 3.2-10. 

The HP8561E spectrum analyzer requires two seconds to sweep from 5020 to 5100 MHz with a 10 
kHz resolution bandwidth. Because of this long sweep time, a 30 kHz resolution bandwidth is selected as 
a compromise for best sensitivity, while minimizing measurement time. The selected parameters for 
MLS are shown as Band 5 in Table 3.2-10. 

As previously stated, the RTCA/DO-233 procedure specified minimum measurement times based 
upon MIL-STD-462D. Using RTCA/DO-233, Appendix A, Section 1.3, the minimum dwell time is 
specified to be 15 ms/kHz. As the resolution bandwidth is increased, the sweep time decreases by the 
same factor. Table 3.2-11 shows the minimum required test times the DO-233 procedure specifies for 
frequency Bands 1 to 5. 



Table 3.2-9: Measurement Bandwidth, Several Standards Compared 



Frequency 
Band 


RTCA 
DO-160D 

[9] 


RTCA 
DO-233 

[3] 


ANSI 

C63.4-2000 

[10] 


ETSI 

EN 301 908-7 
Vl.1.1 [11] 


MIL-STD-462D 

[8] 


30-400 MHz 


10 kHz 


100 kHz 


100 kHz 


100 kHz 


100 kHz 


400- 1000 MHz 


100 kHz* 


100 kHz 


100 kHz 


100 kHz 


100 kHz 


Over 1000 
MHz 


IMHz* 


IMHz 


IMHz 


IMHz 


IMHz 



Specified to be 10 kHz in aircraft commuication/navigation bands for categories M & H. 



24 



Table 3.2-10: Measurement Bandwidths and Sweep Times for Measuring Spurious Radiated Emissions in Aircraft 

Radio Frequency Bands 



Frequency 

Band 
Designation 

& 
(Chamber) 


Aircraft Systems 


MHz 


Resolution 

Bandwidth 

kHz 


Spectrum Analyzer 

Sweep Time (ms) 

(HP8561E) 


1(A) 


VOR & ILS LOC 


105 - 120 


10 


375 


2(A) 


ILSGS 


325 - 340 


10 


375 


3(C) 


DME, TCAS, ATCRBS, 
GPSL2 


960-1250 


100 


73 


4(C) 


GPS LI 


1565 - 1585 


10 


500 


5(C) 


MLS 


5020-5100 


30 


230 



An implied assumption of the minimum required test time estimated in Table 3.2-1 1, is that the PED is 
stationary, and oriented to provide maximum coupling to the test antenna at a given frequency. Eor RC 
testing, it is necessary to perform more measurements at lower frequencies to gain confidence that an 
accurate estimate of the maximum amplitude has been obtained. Table 3.2-12 shows the most recent 
recommendations for a desired number of independent samples for calibrating RCs (DO-160D, Change 1 
[9]). Assuming the stirrer rotation rate is not an even multiple of the spectrum analyzer sweep rate, it can 
be assumed that each spectrum analyzer sweep provides an independent sample for each frequency. 
Multiplying the required number of independent samples by the sweep time can provide an estimate of 
minimum measurement time as shown in Table 3.2-12. The optimal measurement time in a RC can be 
based on a statistical combination of the minimum measurement times estimated in Tables 3.2-11 and 
3.2-12, and will always be less than the multiple of the two. This is because the minimum measurement 
times in Table 3.2-11 assume unchanging electromagnetic boundary conditions in the chamber, and the 
measurement times in Table 3.2-12 prescribe the time required to obtain adequate samples of these 
independent boundary conditions. The spectrum analyzer display can monitor how quickly the maximum 
level stabilizes. Experience has shown that RC measurement times of 120 seconds are adequate to 
determine peak emissions amplitude for each mode and band. 



Table 3.2-11: Estimation of Minimum Required Measurement Time Using RTCA/DO-233, Appendix A Guideline. 



A 


B 


C 


D 


E 


F 


G 


H 


Frequency 

Band 
Designation 


Sweep 

Bandwidth 

(MHz) 


Sweep 
Time 
(ms) 


Dwell Time 
per Sweep 
(ms/MHz) 

[C/B] 


Meas 

Bandwidth 

(kHz) 


DO-233 Min 

Meas Time 

(ms/kHz) 

[(0.015*1000)/E)] 


Sweeps Rqd 

for DO-233 

Min Meas 

Time 

[F/(D/1000)] 


Min Rqd. 
Test Time 

(sec) 
[G*(C/1000)] 


1 


15 


375 


25.00 


10 


1.50 


60 


22.5 


2 


15 


375 


25.00 


10 


1.50 


60 


22.5 


3 


290 


73 


0.25 


100 


0.15 


596 


43.5 


4 


20 


500 


25.00 


10 


1.50 


60 


30.0 


5 


80 


230 


2.88 


30 


0.50 


174 


40.0 



25 



Table 3.2-12: Estimation of Minimum Required Measurement Time in a RC 



A 


B 


C 


D 


Frequency 

Band 
Designation 


Indep. Samples Rqd. for 
Rvb. Cbr. Cal. 


Sweep 
Time (ms) 


Min Meas Time Assuming 

Indep. Samples (sec) 

[B*(C/1000)] 


1 


60 (RC A) 


375 


22.5 


2 


60 (RC A) 


375 


22.5 


3 


18(RCC) 


73 


1.3 


4 


18 (RC C) 


500 


9.0 


5 


18(RCC) 


230 


4.1 



Amplitude Measurement Sensitivity 

Using the frequency band, resolution bandwidth, and designated chamber presented in Table 3.2-10 
and the preamplifiers specified in Tables 3.2-1 through 3.2-3, the spectrum analyzer noise floor and 
preamplifier noise power were measured for each of the five frequency bands, and the results are shown 
in Table 3.2-13. Note that minimum measurement sensitivity is estimated to be 6 dB above the adjusted 
noise floor. The RC losses were taken from previous test data or estimated. From these measurements 
and specifications, the estimated minimum sensitivity for each frequency band was computed and shown 
in Table 3.2-13, Column F. 



Table 3.2-13: Estimation of Minimum Measurement Sensitivities 



A 


B 


C 


D 


E 


F 


Frequency 

Band 
Designation 


Spec. 
Analyzer 
Noise 
Floor 
(dBm) 


Pre-Amp 
Gain (dB) 


Pre-Amp 

Noise 

Power 

(dB) 


Reverb 

Cbr Loss 

(dB)* 


Estimated 

Minimum 

Sensitivity 

(dBm) 

[B-C+D+E+6] 


1 


-93 


61 


24 


6 (RCA) 


-118 


2 


-93 


61 


24 


10 (RCA) 


-114 


3 


-82 


50 


23 


15 (RCC) 


-88 


4 


-93 


55 


25 


25 (RC C) 


-92 


5 


-88 


40 


11 


40 (RC C) 


-71 



* Data based on previous test conducted in chambers 



Description of WLAN Devices and Two- Way Radios 

The off-the-shelf wireless devices tested conformed very well to specified standards and 
interoperability criteria. Tables 3.2-14, 3.2-15, and 3.2-16 lists the brands and model numbers of devices 
tested in each wireless standard. Figure 3.2-7 shows the WLAN devices used in this effort. 802.11b 
devices have a transmit output power range from a 5 mW to 30 mW minimum or 100 mW maximum 
value. A user is able to expand or confine a transmission area with respect to other wireless devices 
operating nearby, when an option to adjust the transmit power level is available in the utility software. 
Several manufacturers of NICs, universal serial bus (USB), or secure digital (SD) devices provide users 
with additional control options or data rates. The llB-2, llB-3, llB-5, 11B12 and llB-13 cards are 
among the 802.1 lb NICs which have the capability to control the transmit output power. The 1 lB-2 card 



26 



was set to its maximum output power of 30 mW, whereas llB-3, llB-5, llB-12 and llB-13 were set to 
their maximum output power of 100 mW. The exact output powers for the other 802.11b devices were 
unknown, since the PC cards' utility software did not contain any feedback to display the value of the 
output power levels of the cards. However, llB-7 and llB-11 are interoperable with the other adapters, 
so they are accepted to be within the output power range. Several 802.1 la devices contain additional data 
rates that are not dictated by the IEEE 802.1 la standard. 







Table 3.2-14: 802.1 la Devices Tested 




DUT 
Designation 


Manufacturer 


Model 


Serial Number 


Host Designation 


Max Output Power 
Ch. Dependent 


llA-1 


Proxim 


Harmony 


052040EX3NVR 


LAP4/LAP6 


50 mW, 200 mW 


llA-2 


Proxim 


Harmony 


051490E0ENVR 


LAP/LAP6 


50 mW, 200 mW 


llA-3 


Linksys 


WPCll 


MBY2402094 


LAP/LAP6 


50 mW, 200 mW 


llA-5 


Intel 


WCB5000 


9009TB00C5B6 


LAP/LAP6 


40 mW, 200 mW 


llA-6 


NetGear 


WAB501 


WAB5A29ZC000671 


LAP/LAP6 


50 mW, 200 mW 



Table 3.2-15: 802. 1 lb Devices Tested 



DUT 
Designation 


Manufacturer 


Model 


Serial Number 


Host Designation 


Maximum 
Output Power 


llB-2 


Cisco 


340 


VMS053313RR 


LAP4/LAP6 


30 mW 


llB-3 


Cisco 


350 


VMS0535026D 


LAP4/LAP6 


100 mW 


llB-5 


Symbol Tech. 


Spectrum 24 PCc 


00A0F830E7EE 


LAP4/LAP6 


100 mW 


llB-7 


Linksys 


WPC54 


G3001203652 


LAP4/LAP6 


95 mW 


llB-11 


Toshiba 


E740 


62058024L 


PDA-2 


N/A 


llB-12 


D-Link Air 


DWL-650H 


H252123003470 


LAP4/LAP6 


100 mW 


llB-13 


NetGear 


WAB501 


WAB5A29ZC000671 


LAP4/LAP6 


100 mW 





Table 3.2-16: 


Bluetooth Devices Tested 




DUT 
Designation 


Manufacturer 


Model 


Serial Number 


Host Designation 


BLUE-2 


3-Com 




HHR13D2800 


LAP4/LAP6 


BLUE-6 


TDK 


Dongle 


SB 10008256 


LAP4/LAP6 


BLUE-8 


Troy 


Windport 


FI-PCM109-68610-24A-0242 


LAP4/LAP6 


BLUE- 10 


Anycom 




Prn Adap 


PRN 


BLUE-11 


Anycom 




PC Card 


LAP4/LAP6 


BLUE- 12 


Toshiba 


Palm 

Bluetooth 

Card 


12001 5 892B 


PDA-1 (SD Card) 



27 



802.11A 



802.11B 



Bluetooth 






Figure 3.2-7: WLAN devices in the form of NICs, a USB dongle, a SD card and integrated into the PDA. 



At the time the 802.11a NICs were purchased, a "Wi-Fi5" certified logo for interoperability was not 
displayed on the cards. Wireless Ethernet Compatibility Alliance (WECA) did not test 802.11a cards for 
interoperability, because there was only one chipset manufacturer in every brand of card. Although, 
WECA certification of an 802.11a NIC only tests interoperability based on the IEEE 802.11a standard. 
The standard only specifies data rates up to 54 Mbps, whereas 802.11a NIC manufacturers offer 
additional data rates in a turbo or 2X mode using proprietary methods. Yet all adapters with this 
capability were able to communicate with the brand of AP used during tests when operated outside the 
chamber. All adapters and APs with this capability were able to communicate outside the chamber with 
ease, and a few hindrances arose during data collection in the chamber. Table 3.2-17 lists the NICs tested 
with mode capability. 

Table 3.2-17: 802.1 la Turbo Data Rates 



Manufacturer 


Turbo Mode Data Rates 


llA-l/llA-2 


12,18,24,36,48,72, 96,108 Mbps 


llA-3 


Up to 72 Mbps 


llA-5 


N/A 


llA-6 


Up to 108 Mbps 



Users can set the data rates on NICs; however, during testing, the data rate field was set to automatic. 
Rates were changed at the AP, and the NICs adjusted their rate accordingly. The AP interface software 
was used to enable the antenna port used during testing to transmit and receive information. Data 
collection for 802.11a/b had a few challenging cases which will be discussed later in this section; but 
overall data were collected as expected from preliminary testing results. 

Bluetooth devices, as seen in the third group of Figure 3.2-7, did not have any option controls and 
usually had a stable link with the test set. Usually, reseating the Bluetooth device with its host solved 
most of the connection failures that occurred between the Bluetooth device and test set. 

FRS and GMRS radios were tested as a pair in the RC with an operator switching channels and 
transmitting audio. Two-way radio tests were straight forward. Table 3.2-18 lists the brands and models 
of devices tested. Figure 3.2-8 shows both types of paired radios used in this effort. 



28 



FRS Radios 



GMRS Radios 





Figure 3.2-8: 4 pairs of FRS and 3 pairs of GMRS radios. 





Table 3.2-18 


: FRS and GMRS Radios Tested 


Pair 
Designation 


Manufacturer 


Model 


Serial Numbers 


FRS-1 


Motorola 


T5420 


165WCB0L6H 


FRS-2 


Motorola 


T5420 


165WCB0L7T 


FRS-3 


Cobra 


FRS 225 


L201279758 


FRS-4 


Cobra 


FRS 225 


L201273388 


FRS-5 


Audiovox 


FR-1438 


112105119 


FRS-6 


Audiovox 


FR-1438 


112105121 


FRS-7 


Midland 


75-17 


00516539 


FRS-8 


Midland 


75-17 


00516537 


GMR-1 


Motorola 


T6400 


175TB WY469 


GMR-2 


Motorola 


T6400 


175TBX1332 


GMR-3 


Audiovox 


GMRS1535 


TTKOl 11 0019481 


GMR-4 


Audiovox 


GMRS1535 


TTKOl 11 0019501 


GMR-5 


Midland 


G-11C2 


15011596 


GMR-6 


Midland 


G-11C2 


15011610 



Wireless Device and Two- Way Radio Radiated Emission Measurements 

Radiated emissions tests were performed in two of the NASA-LaRC RCs, Chambers A and C. Two 
different chambers were used due to chamber characteristics and noise level in specific frequency bands. 
The chamber configuration and test instrumentation used during calibration and emission measurements 
are illustrated in Figure 3.2-2. Test instrumentation consisted of an HP8561E Spectrum Analyzer, an 
HP85644A Tracking Source, RF filters, pre-amplifiers, transmit and receive antennas, and a control 
laptop computer. Transmit and receive antennas were appropriate for the measurement frequency bands 
and included log periodic, dual-ridge horn, and GPS survey. To obtain a lower noise floor, amplify 
signals, and to block out-of-band signals relative to the wireless device transmission frequencies, RF 
filters and preamplifiers were included in the receive path. 

The previously described measurement method (Section 3.2 Measurement Method) was utilized for all 
calibrations and radiated emission tests. The position of a hostAVLAN device and AP antenna were 
similar to positions indicated in Figure 3.2-2. During calibration measurements, the host and WLAN 
device inside the chamber and the test set outside the chamber were powered off. The operator was 



29 



grounded during tests to prevent electrostatic discharge voltages from effecting measurements. Using the 
control software, power measurements were normalized with the calibrated data and the results were 
recorded for each frequency within the test band. 

Noise floor measurements were conducted to determine the ambient environment with hosts, WLAN 
devices, and an operator inside the chamber, but with the hostAVLAN powered off and the Bluetooth test 
set or AP powered on. These measurements were used to verify a quiet RF environment before 
proceeding with radiated emissions tests. 

A minimum test dwell time of 120 seconds was used for all tests where the RC characteristics affected 
the measurements. A dwell time is defined as the time applied for the duration of one test, which 
consisted of either a calibration measurement or an emission measurement where the DUT performed in a 
test mode, at a specific data rate and channel. Transmit cable calibration measurements required only two 
sec, as no RC was needed. RC and receive path calibration measurements were conducted for a dwell 
time of 120 seconds. Emission test dwell times varied depending on the number of channels accessed 
during a test. 




Figure 3.2-9: RC and 802.11a WLAN setup for Band 4 (1565 MHZ - 1585 MHZ). 

Figure 3.2-9 provides a picture of the emissions test setup in Chamber C. Included in the picture are 
the GPS receive antenna, a dual-ridge-horn transmit antenna, a host laptop with wireless PC card 
installed, and an AP antenna. The stirrer, which is not seen in the picture, was located directly across the 
chamber from the horn antenna. 

Figure 3.2-10 illustrates the control and data acquisition hardware located outside an RC. Pictured are 
the HP8561E Spectrum Analyzer and the HP85664A Tracking Source. The local oscillators and four 
other ports of the spectrum analyzer and tracking source were connected in order to synchronize 
frequencies. The picture also illustrates the receive path including cable, filters and preamplifier resting 
on top of the tracking source. Agilent Visual Engineering Environment (VEE) software was used to 
develop control and data recording software that was run on a laptop computer. 



30 




Figure 3.2-10: Control and data acquisition setup outside the RC. 



The 802.11a and 802.11b APs, located outside the chamber, were used as test sets to control data 
transfers and switch data rates and channels while operating in ping storm (PS) and duplex file transfer 
(Xfer) modes. Emission tests were conducted on one WLAN device at a time. The data link between the 
test set and the WLAN device was exercised using three operational modes: idle, PS, and Xfer, while 
swiching data rates and channels. A test consisted of a mode, a data rate, and three channels. During a 
three-minute dwell time, channel switching was conducted at one-minute intervals. This allowed 
approximately one minute of test time at each channel. Host baseline test results were used to select 
laptops for use during emission testing of wireless devices. Selected hosts also included PDAs that 
operated with WLAN cards installed and a printer with wireless capabilities. 

During Bluetooth device emissions testing, an Agilent Technologies E1852B Bluetooth Test Set, 
located outside the chamber, was used to control test modes. Bluetooth emissions tests were performed 
using both idle and normal paging modes. Since Bluetooth protocol uses frequency-hopping techniques, 
no channel switching was done. During a test, a spectrum analyzer was swept for a two-minute dwell 
time and then data were recorded. 

FRS and GMRS radios were tested in pairs in idle mode and voice transmit/receive modes. During 
FRS/GMRS radio emissions testing, the operator used two radios, one in each hand, and talked into one 
radio while receiving with the other radio. Channels were switched every two minutes. 

Test Matrix 

Tables 3.2-19 and 3.2-20 are portions of the 802.11a and 802.11b test matrices used during radiated 
emission testing. The tables include DUT numbers, test modes and channels, and frequency-band 
numbers. Note that tests using idle, PS, and Xfer modes were conducted. Selected data rates and 
channels are indicated for PS and Xfer modes. The illustrated combination of modes, data rates, and 
channels was repeated for each 802.11a and 802.11b WLAN device in the five measurement frequency 
bands. 



31 



Table 3.2-19: 802.1 la Test Matrix 



Device 

Under 

Test 


Test IVIodes and Channels 


Bands 


llA-1 


Idle 


1-5 


llA-1 


Ping Storm AP Data Rate 6 Channels 36 48 64 


1-5 


llA-1 


Ping Storm AP Data Rate 12 Channels 36 48 64 


1-5 


llA-1 


Ping Storm AP Data Rate 24 Channels 36 48 64 


1-5 


llA-1 


Ping Storm AP Data Rate 36 Turbo Channel 42 50 58 


1-5 


llA-1 


Duplex File Xfer AP Data Rate 6 Channel 36 48 64 


1-5 


llA-1 


Duplex File Xfer AP Data Rate 12 Channel 36 48 64 


1-5 


llA-1 


Duplex File Xfer AP Data Rate 24 Channel 36 48 64 


1-5 


llA-1 


Duplex File Xfer AP Data Rate 36 Turbo Channel 42 50 58 


1-5 



Table 3.2-20: 802. 1 lb Test Matrix 



Device 

Under 

Test 


Test IVIodes and Channels 


Bands 


llB-1 


Idle 


1-5 


llB-1 


Ping Storm AP Data Rate 1 Channels 16 11 


1-5 


llB-1 


Ping Storm AP Data Rate 2 Channels 16 11 


1-5 


llB-1 


Ping Storm AP Data Rate 1 1 Channels 16 11 


1-5 


llB-1 


Duplex File Xfer AP Data Rate 1 Channels 16 11 


1-5 


llB-1 


Duplex File Xfer AP Data Rate 2 Channels 16 11 


1-5 


llB-1 


Duplex File Xfer AP Data Rate 1 1 Channels 16 11 


1-5 



Table 3.2-21 illustrates the test matrix used for radiated emissions measurements conducted on 
Bluetooth WLAN devices. As in the previously illustrated matrices, DUT numbers, test modes, and 
frequency bands are included. Only two modes were used, idle and normal paging. All Bluetooth 
devices were tested using this matrix in the five measurement frequency bands. 



Table 3.2-21: Bluetooth Test Matrix 



Device 

Under 

Test 


Test IVIodes 


Bands 


BLUE-1 


Idle 


1-5 


BLUE-1 


Normal Paging 


1-5 



Table 3.2-22 demonstrates a portion of the test matrix used during radiated emissions testing on FRS 
and GMRS radios. The tests required that two radios be paired for communication and transmission. The 
matrix illustrates the radio numbers and pairs, test modes, and frequency bands. The matrix was applied 
for frequency Bands 1 through 5. 



32 



Table 3.2-22: FRS/GMRS Radios Test Matrix 



Device 

Under 

Test 


Test Modes 


Bands 


FRS1&2 


Idle 


1-5 


FRS1&2 


Xmit Voice Count, Channels 1&14 


1-5 


FRS3&4 


Idle 


1-5 


FRS3&4 


Xmit Voice Count, Channel I&I4 


1-5 


FRS5&6 


Idle 


1-5 


FRS5&6 


Xmit Voice Count, Channels 1&14 


1-5 


FRS7&8 


Idle 


1-5 


FRS7&8 


Xmit Voice Count, Channel I&I4 


1-5 


GMR1&2 


Idle 


1-5 


GMR1&2 


Xmit Voice Count, Channel 7&14&15 


1-5 


GMR3&4 


Idle 


1-5 


GMR3&4 


Xmit Voice Count, Channels 1&15 


1-5 


GMR5&6 


Xmit 


1-5 


GMR5&6 


Xmit Voice Count, Channels 1&15 


1-5 



WLAN Device Multipath Interference 

During radiated emission testing in an RC, multipath interference continued to occasionally affect 
communication between APs and WLAN devices. When interference occurred, it caused loss of 
communication between the AP and the WLAN device, making it necessary to repeat tests. Every effort 
was made to maintain communication for an adequate dwell time in order to collect a complete data set of 
measurements. Implementing one or more of the following methods removed many of the multipath 
interference affects: 

1) The AP antenna and WLAN device were placed about one to three inches apart. 

2) A 20 dB attenuator was inserted inline with the AP antenna. 

3) Metal shielding was placed around the DUT, as shown in Figure 3.2-11, to avoid a direct path 
between the AP antenna and the stirrers. 

4) Only one stirrer was used in Chamber A if communication failed after two attempts to collect 
data. 

Other methods utilized to maintain or reestablish communication were available through the WLAN 
PC card. The software interfaces for each WLAN PC card provided communication status and a means to 
rescan for devices. When a rescan failed the NIC was reseated by ejecting it from the PCMCIA slot and 
then reinstalling it. While this slowed the testing process, it did allow the devices to re-associate. 

Disassociation between the 802.1 la/b APs and NICs occasionally occurred as a result of channel 
changes during testing, and recovery was sometimes difficult. A specific example is that 802.11a cards 
had difficulty maintaining association with an AP during turbo mode tests. In these cases, data were 
collected for the specified dwell time with the DUT cycling through one or two of the test channels 
depending on communication status. Where association could not be maintained during a channel 



33 



change, the data collected do not contain measurements for that next channel and is, therefore, 
incomplete. Test log entries were made to indicate incomplete test cases and detail the problems 
encountered. In some cases data were collected on just one channel for three minutes. However, based 
on data from completed tests, changing channels during 802.1 la/b device testing did not significantly 
alter the peak radiated emission measurements and did not affect the final results. 

Table 3.2-24 provides further detail on incomplete tests due to multipath interference. Details include 
specific device designation, data rate, and mode, and the channels not reflected in the data due to 
inadequate communication. 

Other than the multipath interference disruptions, the data collection process proceeded with only a 
few technical inconveniences. The full scope of the testing is indicated in Table 3.2-23 where the total 
number of test cases for 802.1 la/b devices is computed. Out of the combined total of test cases between 
the two technologies, only 4.5% are incomplete. 

Table 3.2-23: Provides the Total Number of Test Cases Taken for Each Wireless Technology Standard 



Wireless 
Technology 


Number of Devices 


Number of Test 
Cases Per Device 


Number of Test 
Bands 


Total Test Cases 


802.11a 


5 


9 


5 


225 


802.11b 


7 


7 


5 


245 



Table 3.2-24: Incomplete Test Due To Multipath Interference 



WLAN 
Device 


Data Rates 


Test Mode 


Omitted 
Channels 


Band 


Comments 


llB-7 


1 

11 
11 
11 


Ping Storm 

File Transfer 

Ping Storm, File Transfer 

Ping Storm, File Transfer 


6&11 

11 
6&11 
6&11 


1 

3 
4 

5 




llB-11 


11 

2 
1 
11 


Ping Storm 
Ping Storm 
Ping Storm 
Ping Storm 


11 
11 
11 
11 


2 
3 
5 
5 
















llA-1 


12 


Ping Storm 


64 


2 




llA-2 


12 


File Transfer 


48&64 


1 




llA-3 


12 

24 

12 

36 (turbo) 


File Transfer 

File Transfer 

File Transfer 

Ping Storm, File Transfer 


48&64 

48&64 

48&64 

all 


1 
1 

2 
3,4,5 


Omitted 



34 




Figure 3.2-11: Metal shielding to reduce multipath interference to the AP antenna. 



3.2,4 Data Reduction 

IEEE 802.11a, IEEE 802.11b, and Bluetooth 

Figures 3.2-13 and 3.2-14 illustrate the data reduction process and results. The process was applied to 
the PED baseline test data set and wireless device emission data set in each frequency band. For the 
purpose of comparison and analysis, large amounts of data were reduced by creating data envelopes, 
which are representative of the maximum measurements for each PED and each WLAN device and host 
combination. Ultimately, these data envelopes were reduced to two composite data envelopes, a PED 
composite envelope and a WLAN device composite envelope, that represent the maximum magnitudes of 
all PEDs and all WLAN devices. The end of the process results in data plots found in Sections 3.3, 3.4, 
and 3.5 comparing PED and WLAN device emissions. 

A general data reduction process is illustrated in Figure 3.2-13. Implementing this process creates 
data envelopes from data sets by determining the maximum (MAX) magnitudes for each frequency within 
a frequency band. The oval shapes illustrated in the figures represent data plots produced for each of the 
five frequency bands. The DUT notation represents PED, host device, or combination of WLAN device 
and host. As input to the reduction process, DUT Data represents measurement data collected during 
PED/host and WLAN device testing using several operating modes. Figure 3.2-13 demonstrates the 
generation of DUT envelopes using measurement data and the creation of composite envelopes from 
individual DUT envelopes. 



DUT Data 



Get Maximum 
at Each Frequency 



DUT Envelopes 



Get Maximum 
at Each Frequency 




" Composite Envelope 



Figure 3.2-13: Data reduction process. 



35 



In this section the notation WLAN is used to refer to a WLAN device and host combination, where the 
host was selected based on lowest emission levels from all PEDs tested (Section 3.2.2 Host Device 
Baseline). WLAN and PED measurement data are illustrated in Appendices A and B, respectively. The 
reduction of this data followed the general process illustrated in Figure 3.2-13. 

The following algorithms summarize the generation of data envelopes and use DUT to refer to PED or 
WLAN data. 

For each frequency band, and for each DUT, 

Max iDUT Emissions \ ah _ Modes UU I Envelope 

For each frequency band. 

Max [DUT Envelope ],„,„, ^ All _ DUT ,_^„^ _,„^, 

Conforming to the data reduction process individual PED and WLAN envelopes, and PED and 
WLAN composite envelopes were generated. PED envelopes are plotted and reported in Section 3.4. 
WLAN envelopes are plotted and shown in Section 3.3. 

Figure 3.2-14 shows the last step in the data reduction process, which plots and compares the final 
PED composite envelope and the final WLAN composite envelope. The two composite envelopes were 
plotted together for each frequency band and are reported in Section 3.5. 



Composite PED Envelope 
Composite WLAN Envelope 

Figure 3.2-14: Composite PEDs and Composite WLAN data reduction and plot (See Section 3.5). 

3.3 Test Results of WLAN Devices 

This section describes the results from the radiated emission tests conducted on WLAN devices. The 
following charts illustrate the WLAN devices' data envelopes organized by measurement frequency 
bands. Sections are labeled with the appropriate frequency bands and include data acquired during 
radiated emissions testing using WLAN devices combined with a host based on 802.11a, 802.11b, and 
Bluetooth standards, and FRS radios and GMRS radios. Each chart contains plots of individual WLAN 
device envelopes, and an envelope that represents the maximums of all WLAN devices. Individual 
devices are designated with a number-letter combination, such as llA-1, llB-5, Blue-2, FRS1&2, or 
GMR3&4, whereas the envelope of all WLAN devices is simply labeled 11 A, IIB, Blue, FRS, or GMR. 
Individual WLAN device envelopes were generated from measured emission data including all PS tests, 
Xfer tests, and idle mode tests. Noise floor data is plotted on charts in Appendix B that illustrate 



36 




individual WLAN device data in each test mode. A WLAN Devices Composite Envelope is the 
maximum at each frequency of all of the individual WLAN Device Envelopes. Note that the WLAN 
Device Composite Envelopes are plotted in green. In all cases, the green Composite Envelope plot masks 
portions or all of individual device traces directly underneath, making it difficult to recognize the 
presence of the individual traces beneath. A description of the processes used for the reduction of data 
and the generation of envelopes is found in Section 3.2.4. Envelope plots that include all WLAN devices 
are also used in charts in Section 3.5. 

The individual WLAN device envelopes were analyzed, and it was determined that devices with the 
highest emissions were randomly distributed across frequency bands, and that no one device can be 
designated as the dominant emitter in all five measurement bands. 

3.3.1 Band 1 (105 MHz to 120 MHz) 

Data presented in Figures 3.3-1 to 3.3-5 were acquired in the aircraft systems frequency band assigned 
to VOR and ILS LOC systems. Each figure plots envelopes for each individual WLAN device and an 
envelope representing all WLAN devices as related to each standard. 



ISM51 11A-1 B1 Envelope 

ISM51 11A-2B1 Envelope 

ISM51 11A-3B1 Envelope 

ISM51 11A-5 81 Envelope 
ISM51 11A-6B1 Envelope 

•ISM51 11A B1 Composite Envelope 




111 112.5 114 

Frequency (MHz) 



Figure 3.3-1: Individual 802.11a WLAN Device Envelopes and 802.11a WLAN Devices Composite Envelope for 
Band 1. 



37 



-50 



-60 



ISM24 1 1 B-1 1 B1 Envelope 

ISM24 1 1B-13 81 Envelope 

ISM24 11B-3B1 Envelope 
ISM24 1 1 B-7 B1 Envelope 



ISM24 11B-12B1 Envelope 
ISM24 11B-2B1 Envelope 
ISM24 11B-5B1 Envelope 
ISM24 11B B1 Composite Envelope 




Figure 3.3-2: Individual 802.11b WLAN Device Envelopes and 802.11b WLAN Devices Composite Envelope for 
Band 1. 



-50 1 



E 

DQ 



O 

O 
Q. 




-100 



-110 



-120 



120 



Figure 3.3-3: Individual Bluetooth WLAN Device Enelopes and Bluetooth WLAN Devices Composite Envelope 
for Band 1. 



38 



-50 



-70 



E 



O 
Q. 



■D -90 



-100 



-110 



-120 



GMRS FRS1&2 B1 Envelope 

GMRS FRS3&4 B1 Envelope 

GMRS FRS5&6 B1 Envelope 

GMRS FRS7&8 81 Envelope 

FRS B1 Composite Envelope 




,«^J|/\^^ 



105 106.5 1C 



109.5 111 112.5 114 115.5 117 118.5 120 
Frequency (MHz) 



Figure 3.3-4: Individual FRS Radio Envelopes and All FRS Radios Composite Envelope for Band 1. 



-GMRS GMR1&2 B1 Envelope 
-GMRSGMR3&4B1 Envelope 
-GMRSGMR5&6B1 Envelope 
-GMRS B1 Composite Envelope 




-120 4 



105 106.5 1 



Figure 3.3-5: Individual GMRS Radio Envelopes and All GMRS Radios Composite Envelope for Band 1. 



39 



3.3.2 Band 2 (325 MHz to 340 MHz) 

Data presented in Figures 3.3-6 to 3.3-10 were acquired in the aircraft systems frequency band 
assigned to ILS GS systems. Each figure plots envelopes for each individual WLAN device and an 
envelope representing all WLAN devices as related to each standard. 



E 
o 

0. 



(0 



0) 
0. 




-100 



-110 



-120 



ISM51 11A-1 B2 Envelope 

ISM51 1 1 A-2 B2 Envelope 

ISM51 1 1 A-3 B2 Envelope 

ISM51 11 A-5 82 Envelope 

ISM51 1 1 A-6 B2 Envelope 

ISM51 1 1 A B2 Composite Envelope 



^'-Mt.Hb 



i| Jll 1 SM51 11A 82 Composite Envelope 



325 326.5 328 329.5 



331 332.5 334 335.5 337 

Frequency (MHz) 



338.5 



340 



Figure 3.3-6: Individual 802.1 la WLAN Device Envelopes and 802.1 la WLAN Devices Composite Envelope for 
Band 2. 



40 



ISM24 11 B-11 B2 Envelope 

ISM24 1 1B-13 82 Envelope 

ISM24 1 1 B-3 B2 Envelope 

ISM24 1 1 B-7 B2 Envelope 



ISM24 1 1 B-1 2 B2 Envelope 

ISM24 1 1 B-2 B2 Envelope 

ISM24 1 1 B-5 B2 Envelope 

ISM24 1 1 B B2 Composite Envelope 



E 



O 
Q. 



■a 
cc 




Figure 3.3-7: Individual 802.11b WLAN Device Envelopes and 802.11b WLAN Devices Composite Envelope for 
Band 2. 



-40 



-50 



_ -60 

E 

QQ 



-100 



-110 ^ 



ISM24 BLUE-10 B2 Envelope 

ISM24 BLUE-11 82 Envelope 

ISM24 BLUE-12 B2 Envelope 

ISM24 BLUE-2 B2 Envelope 
ISM24 BLUE-6 B2 Envelope 

ISM24 BLUE-8 B2 Envelope 

ISM24 BLUE B2 Composite Envelope 




Figure 3.3-8: Individual Bluetooth WLAN Device Envelopes and Bluetooth WLAN Composite Devices Envelope 
for Band 2. 



41 



E 

CQ 

o 



.2 
cc 



-110 




-100 



325 326.5 328 329.5 



331 332.5 334 
Frequency (MHz) 



335.5 337 338.5 340 



Figure 3.3-9: Individual FRS Radio Envelopes and FRS Radios Composite Envelope for Band 2. 




-90 



-110 



325 326.5 328 329.5 



331 332.5 334 
Frequency (MHz) 



335.5 337 338.5 340 



Figure 3.3-10: Individual GMRS Radio Envelopes and GMRS Radios Composite Envelope for Band 2. 



42 



3.3.3 Band 3 (960 MHz to 1250 MHz) 

Data presented in Figures 3.3-11 to 3.3-15 were acquired in the aircraft systems frequency band 
assigned to DME, TCAS, ATCRBS, and GPS L2 systems. Each figure plots envelopes for each 
individual WLAN device and an envelope representing all WLAN devices as related to each standard. 



-50 



^ -70 

E 

m 

o 

^ -80 

o 

Q. 



"5 -90 
ns 

CC 

o 
a. 



-100 



-110 



-120 



phjih 



i''kJr^^ "'^.tVi 




-ISM51 11A-1 B3 Envelope 
-ISM51 11A-2B3 Envelope 
-ISM51 11A-3B3 Envelope 

ISM51 11A-5 83 Envelope 

ISM51 11A-6B3 Envelope 

ISM51 1 1 A B3 Composite Envelope 



990 1020 1050 1080 1110 1140 

Frequency (MHz) 



1170 



1200 



1230 



1260 



Figure 3.3-11: Individual 802.11a WLAN Device Envelopes and 802.11a WLAN Devices Composite Envelope for 
Band 3. 



43 



E 
m 
■o 



5 
o 

Q. 




-100 



-110 



-120 4 



ISM24 1 1 B-1 1 B3 Envelope 

ISM24 11B-12 83 Envelope 

ISM24 1 1 B-1 3 83 Envelope 

ISM24 11B-2B3 Envelope 

ISM24 1 1 B-3 B3 Envelope 

ISM24 1 1 B-5 B3 Envelope 

ISM24 1 1 B-7 B3 Envelope 

ISM24 1 1 B B3 Composite Envelope 



960 990 1020 1050 1080 1110 1140 

Frequency (MHz) 



1170 



1200 



1230 



1260 



Figure 3.3-12: Individual 802.1 lb WLAN Device Envelopes and 802.1 lb WLAN Devices Composite Envelope for 
Band 3. 



-40 



-50 



-ISM24 BLUE-10 B3 Envelope 
-ISM24 BLUE-12 83 Envelope 

ISM24 BLUE-6 B3 Envelope 
-ISM24 BLUE B3 Composite Envelope 



-ISM24 BLUE-11 B3 Envelope 

ISM24 BLUE-2 B3 Envelope 
-ISM24 BLUE-8 B3 Envelope 




960 990 1020 1050 



1080 1110 1140 1170 1200 1230 1260 

Frequency (MHz) 



Figure 3.3-13: Individual Bluetooth WLAN Device Envelopes and Bluetooth WLAN Devices Composite Envelope 
for Band 3. 



44 



E 



O 
Q. 



■a 

(0 

cc 




Figure 3.3-14: Individual FRS Radio Envelopes and FRS Radios Composite Envelope for Band 3. 



-30 



-40 



-GMRS GMR1&2 B3 Envelope 
-GMRS GMR5&6 B3 Envelope 



GMRS GMR3&4 B3 Envelope 

GMRS 83 Composite Envelope 




Figure 3.3-15: Individual GMRS Radio Envelopes and GMRS Radios Composite Envelope for Band 3. 



45 



3.3.4 Band 4 (1565 MHz to 1585 MHz) 

Data presented in Figures 3.3-16 to 3.3-20 were acquired in the aircraft systems frequency band 
assigned to GPS LI systems. Each figure plots envelopes for each individual WLAN device and an 
envelope representing all WLAN devices as related to each standard. 



-50 



^ -70 

E 

^- 

o 

^ -80 

o 

Q. 



-90 



-100 



-110 



f 



AL. .1. M 



ISM51 11A-1 B4 Envelope 

ISM51 11 A-2 B4 Envelope 

ISM51 1 1 A-3 B4 Envelope 

ISM51 11A-5B4 Envelope 
ISM51 11A-6B4 Envelope 
ISM51 1 1 A B4 Composite Envelope 



• U.ii 




'^0iFkf^^*i^ 




-120 

1565 1567 1569 1571 1573 1575 1577 1579 1581 1583 1585 

Frequency (MHz) 

Figure 3.3-16: Individual 802. 11a WLAN Device Envelopes and 802.1 la WLAN Devices Composite Envelope for 
Band 4. 



46 



-50 



^ -70 

E 

m 

o 

^ -80 

o 

Q. 



■a 

(0 
Q. 



-90 



-100 



-110 



-120 



i4r 



ISM24 1 1 B-1 1 B4 Envelope 

ISM24 1 1 B-1 2 B4 Envelope 

ISM24 1 1 B-1 3 B4 Envelope 

- ISM24 1 1 B-2 B4 Envelope 

ISM24 11B-3B4 Envelope 

ISM24 1 1 B-5 B4 Envelope 

ISM24 1 1 B-7 B4 Envelope 

ISM24 1 1 B B4 Composite Envelope 



MilMmMihm. 







rHj» '' r^ ^ 



1565 1567 1569 1571 1573 1575 1577 1579 1581 1583 1585 

Frequency (MHz) 

Figure 3.3-17: Individual 802.1 lb WLAN Device Envelopes and 802.1 lb WLAN Devices Composite Envelope for 
Band 4. 



^ -70 

E 

CQ 



-110 



-120 



-ISM24 BLUE-10 B4 Envelope 
-ISM24 BLUE-11 84 Envelope 
-ISM24 BLUE-12 B4 Envelope 
ISM24 BLUE-2 B4 Envelope 
ISM24 BLUE-6 B4 Envelope 
-ISM24 BLUE-8 B4 Envelope 
-ISM24 BLUE B4 Composite Envelope 



MSJi[- iiifi|.l'f)f||ft«iu.i|) 





\ i.h »Ai.U 



:5jj.^.«^4';^\.^^j^^^^iV'i^'Wui' 




1573 1575 1577 

Frequency (MHz) 



Figure 3.3-18: Individual Bluetooth WLAN Device Envelopes and Bluetooth WLAN Devices Composite Envelope 
for Band 4. 



47 



E 
m 

T3 



O 
Q. 



■a 
cc 




Figure 3.3-19: Individual FRS Radio Envelopes and FRS Radios Composite Envelope for Band 4. 



E 
m 



0) 

o 

Q. 




-100 



-110 



-120 



-GMRS GMR1&2 B4 Envelope 
-GMRS GMR3&4 B4 Envelope 
-GMRS GMR5&6 B4 Envelope 
GMRS 84 Composite Envelope 



1565 1567 1569 1571 1573 1575 1577 1579 1581 1583 1585 

Frequency (MHz) 

Figure 3.3-20: Individual GMRS Radio Envelopes and GMRS Radios Composite Envelope for Band 4. 



48 



3.3.5 Band 5 (5020 MHz to 5100 MHz) 

Data presented in Figures 3.3-21 to 3.3-25 were acquired in the aircraft systems frequency band 
assigned to MLS systems. Each figure plots envelopes for each individual WLAN device and an 
envelope representing all WLAN devices as related to each standard. 




(0 
Q. 



-100 



-110 



ISM51 11A-1 B5 Envelope 
ISM51 11 A-2 B5 Envelope 
ISM51 11A-3B5 Envelope 
ISM51 11A-5 85 Envelope 
ISM51 11A-6B5 Envelope 
ISM51 1 1 A B5 Composite Envelope 



-120 

5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.3-21: Individual 802.1 la WLAN Device Envelopes and 802.1 la WLAN Devices Composite Envelope for 
Band 5. 



49 



-50 



-70 



E 



O 
Q. 



■a 
cc 




-90 



-100 



-110 



-120 



^'^'m^^m^ii4k/4^^ 



ISM24 1 1 B-1 1 B5 Envelope 

ISM24 1 1 B-12 85 Envelope 

ISM24 11B-13 B5 Envelope 

ISM2411B-2 85 Envelope 
ISM2411B-3B5 Envelope 

ISM24 1 1 B-5 B5 Envelope 

ISM2411B-7B5 Envelope 

ISM24 1 1 B B5 Composite Envelope 



5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.3-22: Individual 802.11b WLAN Device Envelope and 802.11b WLAN Devices Composite Envelope for 
Band 5. 



^ -70 




-90 



-100 



-ISM24 BLUE-10 B5 Envelope 
-ISM24 BLUE-11 B5 Envelope 
-ISM24 BLUE-12 B5 Envelope 

ISM24 BLUE-2 B5 Envelope 
-ISM24 BLUE-6 B5 Envelope 
-ISM24 BLUE-8 B5 Envelope 

ISM24 BLUE B5 Composite Envelope 



5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.3-23: Individual Bluetooth WLAN Device Envelopes and Bluetooth WLAN Devices Composite Envelope 
for Band 5. 



50 



-30 



^ -40 

E 



■a -60 



GMRS FRS1&2 B5 Envelope 
GMRS FRS3&4 B5 Envelope 
GMRS FRS5&6 B5 Envelope 
GMRS FRS7&8 85 Envelope 
FRS B5 Composite Envelope 




5052 5060 5068 

Frequency (MHz) 



Figure 3.3-24: Individual FRS Radio Envelopes and FRS Radios Composite Envelope for Band 5. 



-30 




GMRS GMR1 &2 B5 Envelope 

GMRS GMR3&4 B5 Envelope 

GMRS GMR5&6 B5 Envelope 

GMRS B5 Composite Envelope 



E 
OQ 

o 
o 

Q. 

•a 
o 

*•> 

■■5 

O 
Q. 



Figure 3.3-25: Individual GMRS Radio Envelopes and GMRS Radios Composite Envelope for Band 5. 



51 



3.4 Summary of Emission From Standard Laptops and PDAs 

This section describes the results from the radiated emission tests conducted on laptop computers and 
PDAs. The following charts illustrate the PED data envelopes organized by measurement frequency 
bands. Charts are labeled with the appropriate frequency bands and include the reduced data acquired 
during radiated emissions testing using PEDs, such as laptop computers, PDAs and a printer. Noise floor 
data are plotted on charts in Appendix A that illustrate individual PED data in each test mode. Each chart 
contains plots of individual PED envelopes, and a composite envelope that includes all PEDs. In 
addition to the PEDs selected as hosts during WLAN emission testing, the PED envelopes presented here 
include all PEDs tested. The individual PED's designations are listed in the chart legends. Individual 
PED envelopes were generated from measured emissions data, including idle mode and all other PED test 
modes. The PEDs composite envelope is the maximum at each frequency of all the individual PED 
envelopes. Note that the PEDs composite envelopes are plotted in red. A description of the processes 
used for the reduction of data and the generation of envelopes is found in Section 3.2.4. Envelope plots 
that include all PEDs are also used in charts in Section 3.5. 



-50 



-60 



E 
m 



o 

Q. 

■a 



Laptop- 1 Envelope 

Laptop-3 Envelope 

Laptop-5 Envelope 

Laptop-7 Envelope 

PDA-1 Envelope 

PRN Envelope 



Laptop-2 Envelope 

Laptop-4 Envelope 

Laptop-6 Envelope 

— - Laptop-8 Envelope 

PDA-2 Envelope 

PEDS Composite Envelope 




105 106.5 108 109.5 111 112.5 114 115.5 117 

Frequency (MHz) 



118.5 120 



Figure 3.4-1: Individual PED Envelopes and PEDS Composite Envelope for Band 1 (105 MHz to 120 MHz). 



52 



E 
m 

■a 



5 
o 

Q. 

■a 



^ -90 



-100 




-110 



-120 



Laptop-1 Envelope 


Laptop-2 Envelope 


Laptop-3 Envelope 


Laptop-4 Envelope 


Laptop-5 Envelope 


Laptop-6 Envelope 


Laptop-7 Envelope 


Laptop-8 Envelope 


PDA-1 Envelope 


PDA-2 Envelope 


PRN Envelope 


REDS Composite Envelope 



325 326.5 328 329.5 331 332.5 334 335.5 337 338.5 340 

Frequency (MHz) 

Figure 3.4-2: Individual PED Envelopes and PEDS Composite Envelope for Band 2 (325 MHz to 340 MHz). 



E 
m 

i- 
o 

o 

Q. 




-100 



-110 



-120 



-Laptop-1 Envelope 

- Laptop-3 Envelope 
Laptop-5 Envelope 

- Laptop-7 Envelope 
-PDA-1 Envelope 

- PRN Envelope 



Laptop-2 Envelope 

Laptop-4 Envelope 

Laptop-6 Envelope 

Laptop-8 Envelope 

PDA-2 Envelope 

PEDS Composite Envelope 



960 990 1020 1050 



1080 1110 1140 

Frequency (MHz) 



1170 1200 1230 1260 



Figure 3.4-3: Individual PED Envelopes and PEDS Composite Envelope for Band 3 (960 MHz to 1250 MHz). 



53 



E 
m 



o 

Q. 



■a 
a 
CC 




-100 



-110 



-120 



Laptop-1 Envelope 

Laptop-4 Envelope 

Laptop-7 Envelope 

PDA-2 Envelope 



- Laptop-2 Envelope 

- Laptop-5 Envelope 
Laptop-8 Envelope 

- PRN Envelope 



Laptop-3 Envelope 

Laptop-6 Envelope 

PDA-1 Envelope 

REDS Composite Envelope 



1565 1567 1569 1571 



1579 1581 1583 1585 



1573 1575 1577 

Frequency (MHz) 

Figure 3.4-4: Individual PED Envelopes and PEDS Composite Envelope for Band 4 (1565 MHz to 1585 MHz). 



-50 



-60 



E 
m 

o 
o 

Q. 



^ -90 



-100 



-110 



-120 



Laptop-1 Envelope 


Laptop-2 Envelope 


Laptop-3 Envelope 


Laptop-4 Envelope 


Laptop-5 Envelope 

Laptop-7 Envelope 


Laptop-6 Envelope 

Laptop-8 Envelope 


PDA-1 Envelope 


PDA-2 Envelope 


PRN Envelope 


PEDS Composite Envelope 




5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.4-5: Individual PED Envelopes and PEDS Composite Envelope for Band 5 (5020 MHz to 5100 MHz). 



54 



3.5 Comparison of Emissions From Intentionally- and Unintentionally-Transmitting 
PEDs 

The following charts illustrate envelopes that include data from all unintentionally-transmitting PEDs, 
and all intentionally-transmitting 802.11a, 802.11b, and Bluetooth WLAN devices organized by 
measurement frequency bands. Sections are labeled with the appropriate frequency bands and include 
five charts of reduced data produced from data acquired during radiated emissions testing of PEDs and 
WLAN devices. Three charts in each section contain a plot of a PED composite envelope that includes 
all PEDs, and a WLAN composite envelope that includes all WLAN devices. Noise floor data are 
plotted on charts in Appendices A and B that include data on individual WLAN devices and individual 
PED devices in each test mode. The generation of PED envelopes is described in Section 3.4. Note that 
the PED composite envelopes are plotted in red. The reduction of the WLAN device data to a WLAN 
composite envelope is defined in Section 3.3. The WLAN composite envelope plots are presented here in 
green. The envelopes for data acquired during emissions testing of FRS and GMRS radios are included 
in two of the five charts for each frequency band. A description of the processes used for the reduction of 
data and the generation of envelopes is found in Section 3.2.4. 

In general, the data presented in the PED envelope and WLAN device envelope comparison charts 
indicate that radiated emissions from WLAN devices are not higher than PED emissions. One exception 
occurs in Figure 3.5-21 that illustrates Band 5 (5020 MHz to 5100 MHz), having the WLAN envelope 
higher than the PED envelope. Since the transmission frequency of 5.4 GHz for 802.11a devices is 
relatively close to frequency Band 5, this difference is expected. 

Note that in Bands 2, 3, 4, and 5, the FRS and GMRS radio emissions are significantly higher than any 
of the tested WLAN devices. In Bands 2 and 5, the radio emissions are higher than all the PEDs. 

3.5.1 Band 1 (105 MHz to 120 MHz) 









II 






I I I 


PEDS Composite Envelope 

802. 11A Devices Composite Envelope 














II 
II 

! ' ' .iJL 


ujth 




I./'. .jKaj-^-^^'u/^ 






aK}^ ../^ 


n^^Jf^L..UJTL/WV^ 




'V ^^\f\f^ *^^V W M] 1 1 




1 1 1 1 ' ' ' 







Ill 112.5 114 

Frequency (M Hz) 



Figure 3.5-1: 802. 11a Composite WLAN Devices Envelope and PEDs Composite Envelope for Band 1. 



55 



-60 



-PEDS Composite Envelope 

-801. 11 B Devices Composite Envelope 




-100 



-120 



105 



106.5 



108 109.5 



111 112.5 114 
Frequency (MHz) 



115.5 117 



118.5 



120 



Figure 3.5-2: 802.1 lb Composite WLAN Devices Envelope and PEDs Composite Envelope for Band 1. 



PEDS Composite Envelope 

Bluetooth Composite Envelope 




105 106.5 108 109.5 111 112.5 114 115.5 117 118.5 120 

Frequency (MHz) 

Figure 3.5-3: Bluetooth WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 1. 



56 




105 106.5 



Figure 3.5-4: FRS Radios Composite Envelope for Band 1. 



-30 



-40 



-50 



-60 



-70 



-100 




-110 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 



115.5 



118.5 



120 



Figure 3.5-5: GMRS Radios Composite Envelope for Band 1. 



57 



3.5.2 Band 2 (325 MHz to 340 MHz) 




-110 



325 



326.5 



328 



337 



338.5 



329.5 331 332.5 334 335.5 
Frequency (MHz) 

Figure 3.5-6: 802.1 la WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 2. 



340 



-60 



I -80 



-100 



1 1 1 1 1 1 1 


1 M 


III 




J 


k \ 


.j| 






1 ' 1 * 1 l 


\mm 


III 


II 
II 
II 
II 






PEDS Composite Envelope 

802. 11 B Devices Composite Envelope 










II 




1 1 1 1 1 1 1 



331 332.5 334 
Frequency (MHz) 



Figure 3.5-7: 802.1 lb WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 2. 



58 




-110 



-120 



PEDS Composite Envelope 

Bluetooth Devices Composite Envelope 



337 338.5 



325 326.5 328 329.5 331 332.5 334 335.5 

Frequency (MHz) 

Figure 3.5-8: Bluetooth WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 2, 



340 




-110 



325 



326.5 



328 329.5 



331 332.5 334 
Frequency (MHz) 



335.5 337 



338.5 



340 



Figure 3.5-9: FRS Radios Composite Envelope for Band 2. 



59 



I 




-100 



340 



Figure 3.5-10: GMRS Radios Composite Envelope for Band 2. 



3.5.3 Band 3 (960 MHz to 1250 MHz) 



% -70 




-90 



-100 



-PEDS Composite Envelope 
802.11 A Devices Composite Envelope 



960 



990 



1020 



1050 



1080 1110 1140 

Frequency (MHz) 



1170 



1200 



1230 



1260 



Figure 3.5-11: 802.1 la WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 3. 



60 




-100 



-110 



-120 



- PEDS Composite Envelope 

- 802. 11 B Devices Composite Envelope 



960 



990 



1020 1050 1080 1110 1140 1170 1200 1230 1260 
Frequency (MHz) 

Figure 3.5-12: 802.1 lb WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 3. 




-PEDS Composite Envelope 
-Bluetooth Devices Composite Envelope 



1080 1110 1140 

Frequency (MHz) 



Figure 3.5-13: Bluetooth WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 3. 



61 



-30 1 




Figure 3.5-14: FRS Radios Composite Envelope for Band 3. 




Figure 3.5-15: GMRS Radios Composite Envelope for Band 3. 



62 



3.5.4 Band 4 (1565 MHz to 1585 MHz) 




^ -90 



-100 



-110 



-120 



^*^-'^"^XvV^\uJ 



-PEDS Composite Envelope 
802.1 1 A Devices Composite Envelope 



1565 1567 1569 1571 1573 1575 1577 1579 1581 1583 1585 

Frequency (MHz) 

Figure 3.5-16: 802.1 la WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 4. 



-50 n 



E 

CQ 



^ -90 



-100 




-110 



-120 



1579 1581 1583 1585 



1565 1567 1569 1571 1573 1575 1577 

Frequency (MHz) 

Figure 3.5-17: 802.1 lb WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 4. 



63 



-50 



-60 



-70 
m 

I -80 
o 

Q. 



.5 
'■B 

(0 



-100 



-110 



-120 



A/i Mi 1. 




k 


jdLxL 


ii «Il iuii 


vAA«^»v««TV^^ 


A*fV 


^ 


pFVH 


JwV^ 


WM' ^ 








11 ji 




|i i : 








^rm¥\J 


^^/Vl/wWfWj 


WiArtMiA 


ph 


^ 


WIn 


iy 


; If'! 

1 1 1 1 1 

1 










PEDS Composite Envelope 

Bluetooth Devices Composite Envelope 




! I I 






1 
1 
\ \ \ 


—I 


III 
III 
\ \ \ \ 







1565 



1567 



1569 



1571 



1579 



1581 



1583 



1573 1575 1577 
Frequency (MHz) 

Figure 3.5-18: Bluetooth WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 4. 



1585 




HaA/^ 



M WrA 



w 




^/v/VW^ 




1573 1575 1577 

Frequency (MHz) 



Figure 3.5-19: FRS Radios Composite Envelope for Band 4. 



SA^rt^vA^ 



^ 



64 



5) -70 






-100 




Figure 3.5-20: GMRS Radios Composite Envelope for Band 4. 



3.5.5 Band 5 (5020 MHz to 5100 MHz) 



-50 n 




-100 



-110 



-120 



-PEDS Composite Envelope 
802.11 A Devices Composite Envelope 



5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.5-21: 802.1 la WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 5. 



65 



-50 



-60 



-70 



E 
m 



I -80 
o 

Q. 



^ -90 
cc 




-100 



-110 



-120 4 



-PEDS Composite Envelope 

• 802.11 B Devices Composite Envelope 



5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 

Frequency (MHz) 

Figure 3.5-22: 802.1 lb WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 5. 



5100 



-50 



-60 



-70 
? 

DQ 

I -80 

O 
Q. 



(0 

'i -90 
cc 



-100 



-110 



-120 



1 1 


II 
II 
II 






PEDS Composite Envelope 

Bluetooth Devices Composite Envelope 








III 










III 
III 


%m 






v^rj/i^^ 




III 






III 






III 
III 







5020 5028 5036 5044 5052 5060 5068 5076 5084 5092 5100 

Frequency (MHz) 

Figure 3.5-23: Bluetooth WLAN Devices Composite Envelope and PEDs Composite Envelope for Band 5. 



66 




Figure 3.5-24: FRS Radios Composite Envelope for Band 5. 




Figure 3.5-25: GMRS Radios Composite Envelope for Band 5. 



67 



3.6 Summary of Maximum Emissions from WLAN Devices and FRS/GMRS Radios 

This section summarizes maximum emission results reported in earlier sections for WLAN devices, 
two-way radios and computer laptops/PDAs. In addition, comparisons with corresponding FCC and 
RTCA/DO-160 [9] emission limits are reported. 

3.6.1 Summary of Maximum Emission Results 

Table 3.6-1 summarizes previously presented emission data by reporting the maximum emission value 
of different device groups for each measurement band. The device groups include 802.11b, 802.11a, 
Bluetooth, FRS radio, GMRS radio, and Laptop/PDAs. The corresponding aircraft radio-navigation 
systems with frequency spectrum aligned within the emission measurement bands are also shown. These 
systems are potentially affected by any high emissions within the their measurement bands. These 
emission data from Table 3.6-1 are used in the safety margin calculations in Section 5. 

Figure 3.6-1 plots emission data from Table 3.6-1. It can be observed that emission from the GMRS 
radios are the highest, followed by FRS radios. Highest emissions are from the GMRS radio at -28.5 
dBm in Band 2 and -33 dBm in Band 5. (Note: lines in Figure 3.6-1 are for linking the data points at the 
markers. Their magnitudes between the markers have no significant values). In Band 2, the GMRS radio 
emission exceeded the laptop/PDA emission by about 30 dB. 

Figure 3.6-1 also shows that maximum emissions from the WLAN devices are generally lower than 
maximum emissions from the laptop/PDA devices in all five bands. One exception is 802.11a emissions 
in Band 5 with the maximum emission level at -52 dBm. High emission from 802.11a devices in this 
band is not unexpected since both the 802.1 la band and Band 5 are close in the 5-GHz range. MLS is the 
only system in this band, and the risk to MLS is viewed as low due to lack of installed MLS systems in 
the US. 

Emissions in Band 5 from other WLAN devices and laptop/PDA devices are lower in the 
measurement noise floor as evidenced by data aggregated near -78 dBm. 



Table 3.6-1 Maximum Emission from WLAN Devices/ Two-way Radios in Aircraft Bands (in dBm) 



Measurement 
Band 


Frequency 
(MHz) 


802.11b 


Blue- 
tooth 


802,11a 


FRS 
Radio 


GMRS 
Radio 


Laptops 
PDAs 


Aircraft 
Bands 


Bandl 


105 - 120 


-78.2 


-66.8 


-74.2 


-90.7 


-79.3 


-68.0 


LOC, VOR 


Band 2 


325 - 340 


-75.7 


-77.2 


-71.8 


-37.2 


-28.5 


-58.7 


GS 


Band 3 


960 - 1250 


-65.3 


-49.7 


-57.7 


-43.5 


-44.7 


-45.7 


TCAS, ATC, 

DME/TACAN, 

GPSL2 


Band 4 


1565 -1585 


-67.7 


-81.7 


-65.2 


-60.2 


-57.0 


-55.8 


GPS LI 


Bands 


5020-5100 


-77.7 


-78.2 


-52.0 


-38.2 


-33.0 


-77.0 


MLS 



68 



E 

c 
o 
"co 

(0 

E 

LU 

E 

E 
'x 

OS 




-100 





-802.11b 






OAO 1 1 o 


A 


Bluetooth 


_^__ 


- FRS Radio 


-^1^- 


- GMRS Radio 


— •— 


- Laptops/PDAs 



Band 1 Band 2 Band 3 Band 4 

Measurement Band 



Bands 



Figure 3.6-1: Maximum emission from WLAN, Bluetooth devices, FRS/GMRS radios and Laptops/PDAs. 



3.6.2 Comparison with Emission Limits 

Table 3.6-2 shows the FCC Part 15.109 [16] and 15.209 [17] limits for unintentional and intentional 
radiators, the RTCA/DO-160 Category M limits, and the FCC spurious emission limits for FRS/GMRS 
radios (FCC 95.635 [18]). RTCA/DO-160 Category M emission limit is selected for comparisons with 
spurious emissions from passenger carry-on electronic devices since these devices can be located in the 
passenger cabin or in the cockpit of a transport aircraft, where apertures (such as windows) are 
electromagnetically significant. The quote below is the definition for Category M radiated emissions limit 
specified in RTCA/DO-160 Section 21 [9]: 

" Category M : 

This category is defined for equipment and interconnected wiring located in areas where 
apertures are em significant and not directly in view of radio receiver's antenna. This 
category may be suitable for equipment and associated interconnecting wiring located in 
the passenger cabin or in the cockpit of a transport aircraft'' 

For the RTCA/DO-160 Category M limit listed in Table 3.6-2, the limit value for each measurement 
band is chosen to be the lowest limit of the aircraft bands within it. As an illustration, the emission 
measurement Band 3 would cover TCAS, ATCRBS, DME, GPS L2 and GPS L5. The emission limit for 
the whole measurement band is chosen to be the lowest limit of all the systems listed. In this case, the 
lowest value is 50 dB|LLV/m for TCAS, DME and ATCRBS since the limits for GPS L2 and GPS L5 are 



69 



higher. In addition, the emission limit for each aircraft radio band is chosen to be the lowest value 
between its lowest and highest frequency limits. 

To compare with measured emission data in dBm, the field limits in FCC Part 15 and the RTCA/DO- 
160 Category M are converted to the equivalent Effective Isotropic Radiated Power (EIRP) using 
Equation 3.6-1. 



EIRP = 



E-AttR^ 
12071 



(Eq. 3.6-1) 



where EIRP = Effective Isotropic Radiated Power (W) 

E = Electric Field Intensity at distance R (V/m) 

R = Distance (m) 

Ideally, E field measurement is taken in the direction of maximum radiation from the test device. To 
convert power, EIRP, from watts to dBm, use the expression 10 * log(lOOO^EIRP). For the RTCA/DO- 
160 limit given in dBjuV/m, the unit is converted to V/m before applying Equation 3.6-1. 





Table 3.6-2 


-: Estimated FCC and RTCA spurious 


radiated emission limits 




FCC Part 15 
Limit 

(|a,V/m @ 3m) 


RTCA/DO-160 
Category M Limit 

(dB^V/m @ Im) 


FCC Part 15 
Limit 

{EIRP, dBm) 


RTCA/DO-160 
Category M Limit 

{EIRP, dBm) 


FCC FRS/GMRS 
Radio Limit 

{TRP,dBm) 


Bandl 


150 


35 


-51.7 


-69.8 


-13 


Band 2 


200 


52.9 


-49.2 


-51.9 


-13 


Band 3 


500 


50 


-41.2 


-54.8 


-13 


Band 4 


500 


53 


-41.2 


-51.8 


-13 


Bands 


500 


71.8 


-41.2 


-33.0 


-13 



Emissions measured using a RC, on the other hand, provide results in "total radiated power" (TRP) 
within the measurement resolution bandwidth. TRP is different from EIRP except for antennas or devices 
with an isotropic radiation pattern. Rather, 



EIRP (dBm) = TRP (dBm) + Do (dB), 



(Eq. 3.6-2) 



where Dq is directivity, or maximum directive gain of the test device. Directive gain of any device is a 
measure of radiated power as a function of aspect angle referenced to the isotropic value. 

For spurious emissions, Dq is the directivity at the spurious emission frequency of interest. Do is 
usually difficult to measure or calculate since maximum radiation angles and radiation mechanisms for 
spurious emissions are often not known. Maximum theoretical estimation of Dq based on device size 
tends to significantly over-estimate the real directivity, especially at high frequency, because the device 
geometry is typically not designed to radiate efficiently as an antenna as assumed in the theoretical 



70 



estimation. There are other theoretical statistical developments to estimate the "expected" directivity for 
non-intentional radiators [19]. These developments are yet to be validated or widely accepted. Additional 
details on expected directivity are discussed in Section 3.6.3. 

For simplicity, we assume that the WLAN devices (plus the host computer laptops/PDAs) have unity 
Dg for spurious emission. Thus, TRP is assumed to be the same as EIRP at all spurious frequencies of 
interest. This assumption introduces an uncertainty level equal to Dg, according to Equation 3.6-2. For a 
dipole antenna with small electrical length, Dg is close to 1.76 dBi (or dB relative to isotropic). For a 
half-wave dipole, Dg is close to 2.15 dBi. Thus, it is reasonable to assume for devices up to one-half a 
wavelength in size, the uncertainties should not be much more than 2-5 dB. This level of uncertainty is 
considered acceptable for a first order comparison. 

Section 3.6.3 computes the "expected" directivity using formulas provided in [19]. For a device 0.5 m 
in size (approximately the maximum size of an open laptop computer), the expected directivity is between 
5 dB near 100 MHz and 9 dB near 5 GHz. These expected directivity values are provided for information 
purposes only. The method used is yet to be proven or widely accepted. 

For FRS and GMRS radios, FCC 95.635 [18] dictates the attenuation for frequency outside of the 
vicinity of the center frequency is at least 43 + lOlog(Pc) dB, where Pc is carrier frequency power in 
watts. For 0.5-watt FRS radios and 2-watt GMRS radios, the attenuation below carrier power is 40 dB for 
FRS radios and 46 dB for GMRS radios. As a result, the calculated emission limits are -13 dBm for both 
FRS and GMRS radios. 



-20 1 



-30 



-40 



E 

m 

c 

w 

E 

LU 



X 
OS 



-60 



-70 



-80 



-90 







• 

* 


^ OAO -1 -1 h 


r-i OAO -i -i o 




* 




-A y- — - -I\ 


t^ Bluetooth 

— • — Laptops/PDAs 

— A- FCC Part 15 
Limit (EIRP) 

-• - DO-160CatM 
Limit (EIRP) 


A- ■ 




■•^vv^* 


>^-^ ^ 


tr 




•^— ^ 


^^X\ 




' A 




\ ^\ 








A 

Emission + Limits 
Wireless + Laptops 



Band 1 Band 2 Band 3 Band 4 

Measurement Band 



Bands 



Figure 3.6-2: Maximum emissions from WLAN devices, laptops/PDAs and comparison with FCC and RTCA/DO- 
160 equivalent EIRP limits. 



71 



(0 

E 

LU 



X 



-10 



-20 



m 

S -40 



-50 
-60 
-70 
-80 
-90 
-100 



/TN " " " " " /In " " " " " 7i\ " " " " " 7In " " " " " yK 




X 


X FRS Radio 

- ->i^ - GIVIRS Radio 

— • - DO-ieOCatiVI 
Limit (EIRP) 

— X ■ FCC limit 
GMRS/FRS 
(TRP) 


/ ^--~ V ^v" ^ 






/ * / 




^ / / 
/ / 

/ / 
/ / 




1 
1 

1 
1 




X 

Emission + Limits 
FRS & GMRS Radio 

II 





Band 1 



Band 2 Band 3 Band 4 

Measurement Band 



Bands 



Figure 3.6-3: Maximum emission from two-way FRS/GMRS radios and comparison with FCC limits. 



Figure 3.6-2 shows emissions from laptops/PDAs and WLAN devices are lower than corresponding 
FCC equivalent EIRF limits. However, emissions from laptops/PDAs and Bluetooth devices are higher 
than the RTCA/DO-160 Category M equivalent EIRP limits in Band 1 and Band 3. In addition, WLAN 
device emissions are lower than the emissions from the laptops/PDAs, except for 802.11a emissions in 
Band 5. It can be argued that emissions from the measured WLAN devices, while being higher than 
RTCA/DO-160 Cat M limits, do not pose significantly higher risk to aircraft radio receivers than 
emissions from standard laptop/PDA devices. 

For FRS/GMRS radios. Figure 3.6-3 shows emissions are still below the FCC maximum out-of-band 
emission limit of -13 dBm for these devices. Figures 3.6-1 and 3.6-3 show spurious emissions in OS 
band from GMRS radios can be 23 dB higher than RTCA/DO-160D Category M limit, and 30 dB higher 
than the maximum laptop/PDA emissions in the same band. The threat of interference from these two- 
way radios can be significantly higher than from the laptops/PDAs. 

3. 6. 3 Expected Directivity Estimation 

The comparisons above were between the TRP from the devices and the FCC Part 15 and RTCA/DO- 
160 Cat. M equivalent EIRP limits, assuming unity directivity. For devices with directivity different than 
unity, the limits must be adjusted downward by the amounts equal to the devices directivity in dB, which 
can vary with device size, frequency and geometry. 

Reference [19] provides a method to estimate the expected directivity derived from a statistical 
approach. Using equations given, expected directivity of a device can be estimated if its maximum 



72 



dimension is known. For a laptop computer with the maximum dimension of 0.5 m (open screen 
configuration), the expected directivity is shown in Figure 3.6-4. This figure shows the results of three 
calculations: 1) theoretical maximum directivity for a high gain antenna of the same size, 2) expected 
directivity for 1 -planar cut measurement, and 3) expected directivity for 3-planar cut measurement. The 
3-planar cut expected directivity is between five and eight dB for frequencies in Band 4 (GPS) and below, 
and less than nine dB in Band 5 (MLS). 



20 1 
1 

16 
14 



CQ 



Expected Directivty, 1 -Planar Cut 

— - Expected Directivity, 3-Planar Cut 
Intentional High Gain Antenna 




I 10 

o 
o 

S 8 

6 
4 
2 



100 



1000 
Frequency (MHz) 



10000 



Figure 3.6-4: Expected spurious emission directivity of a 0.5 m device. 



4 Aircraft Interference Path Loss Determination 

Aircraft IPL is the second of the three components needed for assessing the potential of interference 
from RF sources to aircraft receivers. Using World Jet Inventory [20] as a guide, there are about 35 
different types of operational, commercial jet airplanes built in the US and Western Europe with a 
capacity of 30 seats or more. Each aircraft type and series has a unique configuration of antenna 
placements and radio receiver installations. These variations may result in widely different IPL values. 

The following sections describe a recent effort to measure IPL for various radio receiver systems on 
six B737s and four B747s. The IPL results are summarized and presented along with other previously 
available data for comparison. 



73 



4.1 Interference Path Loss Measurements on B737s and B747s 

Previous investigations [1] identified deficiencies in available IPL data for a reasonable risk 
assessment of interference to receiver systems from PEDs. To address that issue, NASA entered into a 
cooperative agreement with UAL and EWI to conduct additional IPL measurements and to address 
several technical issues. One issue was to measure additional IPL data using a thorough and consistent 
set of procedures. Another issue concerned aircraft-to-aircraft repeatability. This repeatability issue 
resulted in measurements on six similar B737-200 and four similar B747-400 aircraft. The aircraft in 
each of the two groups were acquired by UAL at approximately the same time, and, therefore were 
similarly configured. 

Other technical issues include investigating the effectiveness of risk mitigation techniques, such as 
treating exit door seams and windows with conductive tape and films. New instrumentation tools for 
assessing health of aircraft cables and antennas were demonstrated. Preliminary on-aircraft operational 
testing of susceptibility of aircraft systems to Ultrawideband (UWB) interference signals was also 
conducted when the schedule permitted [21]. 

For this report, only the IPL results from unmodified aircraft configurations that are relevant to 
wireless interference are reported. IPL data of modified aircraft configurations for side studies, which 
may have conductive tapes and film over aircraft windows and doors, are excluded. These configurations 
are not representative of an in-service aircraft. 

The IPL measurements were performed during three one-week visits to the Southern California 
Aviation facility in Victorville, California. UAL provided the flight-ready airplanes, along with fuel, 
engineering and mechanic support for this effort. These airplanes were temporarily put in storage 
configuration due to September 1 1 terrorist events that resulted in lower demand in passenger travel and 
an increase in surplus capacity. NASA provided measurement instrumentation, data acquisition and test 
control software development and support, and staff. EWI was tasked to lead the overall effort and to 
conduct analysis. 

IPL measurements were conducted on the six B737-200 airplanes for the VOR/LOC, VHF-1 Comm., 
GS, TCAS, and GPS systems. The interference source, simulated with dipole and horn antennas, was 
positioned to radiate toward each of the windows and the door exits on one side of the aircraft. In 
addition, full IPL measurements were also conducted on two B737s with the transmit antenna positioned 
at all seat locations including locations between seats (on one side of the aircraft). 

IPL measurements were also conducted on the four B747-400 aircraft for the LOC, VHF-1 Comm., 
GS, TCAS, GPS and SatCom systems. Due to large aircraft size and the number of windows and doors, 
IPL was measured with the transmitting antenna positioned only at selected windows considered closest 
to the receiving aircraft antenna and to provide the lowest path loss values. For systems with antennas on 
top of the aircraft, including VHF-1 Comm., GS, TCAS, GPS and SatCom, these locations include all 
windows on one side of the upper deck. For LOC and GS systems with their antennas located behind the 
nose radome, IPL measurements were conducted (with the transmit antenna) at the first 20 windows on 
one side of the lower deck. These windows were closest to the antennas in the radome. Figure 4.1-1 
shows images of B737 and B747 aircraft at the measurement site. 

The following subsections, 4.1.1 and 4.1.2, describe the measurement method and IPL results. 



74 




Figure 4.1-1: (a) B737-200 and (b) B747-400 aircraft at the measurement site. 



4, 1. 1 IPL Measurement Method 

It is assumed that for PEDs interference problems, the interference source is located within the 
passenger cabin, and the victims are aircraft radio receiver systems. A common path of PED interference 
is through the windows or door seams, along the aircraft body, and into the aircraft antennas. The 
interference signal picked up by the antennas is channeled back into the receivers to potentially cause 
interference if they are higher than the receiver interference thresholds. 

Figures 4.1-2 and 4.1-3 illustrate typical radio receiver interference coupling paths and a setup for 
conducting IPL measurements. The setup shows a tracking source is used to provide RF power to the 
transmit antenna, and a spectrum analyzer is used to measure the signal received by the aircraft antenna. 
The frequency-coupled spectrum analyzer and tracking source pair allows for frequency sweeps, resulting 
in more thorough measurements and reduced test time. Swept CW was preferred over discrete frequency 
measurement, according to RTCA/DO-233. A pair of test cables is used to connect the instruments to the 



75 



aircraft antenna cable and to the transmit antenna. An optional amplifier may be needed to increase the 
signal strength depending upon the capability of the tracking source and the path loss level. A pre- 
amplifier may be needed in the receive path near the spectrum analyzer for increased dynamic range. 
This pre-amplifier (not shown in Figure 4.1-3) may be internal to the spectrum analyzer. 

In the actual measurements, two independent measurement systems were used for concurrent 
measurements on two airplanes at a time. While the basic set up for each system was the same as shown 
in Figure 4.1-3, the performance and capabilities of the instruments were different. This difference 
caused amplifiers and pre-amplifiers to be used in one setup but not the other. In one setup, the tracking 
source and the spectrum analyzer were combined in one unit with an internal pre-amplifier. The other set 
up included a separate spectrum analyzer and a tracking source that delivered much higher output power. 
In either case, correction factors were applied to ensure correct final IPL results. 



Aircraft Antenna 




Aircraft Fuselage 



Windows and Doors 



Figure 4.1-2: A typical radio receiver interference coupling path for a top mounted aircraft antenna. 



Coupling 
sPath 



Spectrum 
Analyzer 



Tracking 
Source 




"^^^^Aircraft 
Window 



Aircraft 
Cross- 
Section 



Figure 4.1-3: A typical setup for conducting an IPL measurement. 



76 



In Figure 4.1-3, IPL is defined to be the ratio, or the difference in dB, between the power radiated from 
the transmit antenna at location (1) to the power received at location (2). For GPS, IPL is defined to be 
the difference in power between location (1) and (3). Or, 



IPL = P^(i) - P^ (2) for most systems, and 
IPL = P\i)-P\3) for GPS, 



(Eq. 4.1-1) 
(Eq. 4.1-2) 



where P (i) is power transmitted at point (1), and P (2) , and P (3) are power received at points (2) 
and (3), in dBm, respectively. 

The antennas used in the measurement include dipoles (a set of dipoles with baluns covering different 
frequency ranges) for frequencies in the GS band and below, and a dual-ridge horn antenna for the 
frequencies in the TCAS band and above. No corrections were made to account for the transmit antenna 
gain as performed on many data sets documented in RTCA/DO-199 and RTCA/DO-233. The proximity 
of the transmit antennas and their surroundings, such as walls, seats, windows, table trays, would have 
large affects on the true antenna gain, and that free-space antenna gain is viewed as not the appropriate 
correction factor. The true antenna gain is not known in the presence of the obstacles. Transmit antenna 
gain correction was not applied to at least one set of data in RTCA/DO-199. It was also unclear if the 
same gain correction was made to all data in DO-233. In this effort, it is considered best not to correct for 
the free space antenna gain in the definition for IPL for the reasons stated. However, free-space antenna 
gains, as provided by the antenna manufacturers, are shown in Table 4.1-1 that can be used to factor in the 
transmit antenna free-space gain, if so desired. 

Table 4.1-1: Transmit Antenna Free-Space Gain (dBi) 



Aircraft 
Systems 


Spectrum 
(MHz) 


Measurement 

Frequency Range 

(MHz) 


Transmit 
Antenna Type 


Free-Space 

Antenna Gain 

(dBi) 


VHF-Com 


118-137 


116-138 


Dipole 


2.1 


LOCATOR 


LOC: 108.1-111.95 
VOR: 108-117.95 


108-118 


Dipole 


0.9 


GS 


328.6-335.4 


325-340 


Dipole 


1.9 


TCAS 


1090 


1080-1100 


Dual-Ridge 
Horn 


7.4 


GPS (LI) 


1575.42 ± 2 


1565 - 1585 


Dual-Ridge 
Horn 


9.6 


SatCom 


1545-1559 


1530-1561 


Dual-Ridge 
Horn 


9.6 



In the actual measurement, the test cables at (1) and (2) were connected together and a "through" 
swept measurement was made for the total system loss. The test cables were then reconnected at points 
(1) and (2) (points (1) and (3) for GPS) and another swept-frequency measurement was made. The 
instrument settings were maintained to be the same as during the "through" system loss measurement . 
The receive power difference between the maximum of the first measurement data and the maximum of 
the second measurement data gave the IPL for that particular transmit antenna location. This calculation 
for IPL was conducted during data post-processing. 



77 



As shown in Figure 4.1-3, a transmit antenna was used to simulate an interference source. The tuned 
dipole transmit antenna was used for measurements in the LOC, VOR and GS bands, and a dual-ridge- 
hom antenna was used for measurements in the TCAS, GPS and SatCom bands. 

For most systems, IPL included aircraft cable loss, since receiver susceptibility thresholds were 
specified at the receiver antenna port. For GPS, interference thresholds were specified at the output of a 
passive GPS antenna. Thus, IPL for GPS should not include the antenna cable loss. The test cable should 
connect directly to the GPS antenna output or very close to it, and the spectrum analyzer measured the 
power at the output of the antenna directly. Since the aircraft active GPS antenna was powered with the 
help of a DC bias-tee, the bias-tee was included in the total system loss measurement. 

The active GPS antenna pre-amplifier gain was removed during post processing, giving higher IPL. 
This step was required in the GPS receiver's Minimum Operating Performance Standards (MOPS), as the 
interference threshold was specified at the output of a passive antenna, or at the output of an active GPS 
antenna, but before the pre-amplifier stage. 

The measurement process for each system on each aircraft typically involved the following steps: 

1. Conduct 1 -meter path loss measurement. IPL was measured with the transmit antenna 
positioned one meter from the aircraft antenna. This simple step established a baseline 
measurement and helped detect any excessive aircraft antenna cable loss. Excessive cable 
loss could indicate possible signs of connector corrosion in the path. These data were not 
needed to compute the IPL. 

2. Configure the spectrum analyzer to the proper reference level, resolution bandwidth, 
attenuation level and desired measurement frequency band. Configure the tracking source to 
track the frequency sweep of the spectrum analyzer. Set the tracking source output to desired 
power level. 

3. Measure test cable and aircraft cable "through" losses. 

4. Position the transmit antenna at a desired location, typically near a window or door. Point the 
antenna to radiate toward a window or door seam. 

5. Clear spectrum analyzer's trace. Set spectrum analyzer to "Trace Max Hold" and sweep 
continuously across the desired measurement band. 

6. Scan the transmit antenna slowly along the door seam, while the spectrum analyzer is still set 
at "Trace Max Hold". No scanning was needed at the windows due to small window sizes. 

7. Record trace and the peak marker value. For systems that experience narrowband peaks 
caused by strong local transmitters such as LOC, position the marker at the peak of the 
broadband envelope while avoiding the narrowband peaks. Record data at this marker 
location. 

8. Change polarization and repeat from step 2 so that both vertical and horizontal polarizations 
of the transmit antenna are included. 



78 



9. Relocate the transmit antenna to another window/door and repeat from step 4. 

Post processing involved removing the measured system "through" loss from the total path loss data. 
The system loss includes the effects of test cable losses, amplifier gains, and other types of losses/gains in 
the measurement path. Active GPS pre-amplifier gain is also removed in the final results. 

Figure 4.1-4 shows a 1 -meter path loss measurement near a B737 VOR/LOC antenna located in the 
tail. A 1 -meter path loss measurement was conducted to check the integrity of the aircraft antenna path. 
The results were not used to calculate IPL and are not reported in this document. Of all systems 
considered for IPL measurement, only the VOR/LOC s antenna on the B737-200 is located in the tail. 
All other systems have their antennas located either on top of the aircraft, such as TCAS, GPS and VHP 
Comm, or behind the nose radome, such as GS. On a B747, all systems with IPL measurements have 
their antennas in the nose (GS and LOG), or on top above the upper deck windows (TCAS, VHF-Com, 
SatCom, GPS). 

Figure 4.1-5 shows a measurement being conducted with the transmit antenna at a window, and the 
computer and software used for data acquisition. Instruments and computers were located within the 
passenger cabin. Spurious emissions from these equipment were too low to be measurable or to affect the 
measurement. In contrast, the output signal from the tracking source was 10 dBm or higher depending 
upon whether an external amplifier was used. 




Figure 4.1-4: Conducting 1-meter path loss baseline measurement for the LOC antenna in the B737's tail. The 
reference transmit antenna is one meter from the receive aircraft antenna. The two VOR/LOC antennas are parallel 
to each other and are embedded horizontally within the top edge of the aircraft tail. 



79 




Figure 4.1-5: IPL measurement at window locations, (a) A dipole was used as transmit antenna for LOC, VOR, GS 
and VHF-Com. (b) A dual ridge horn antenna was used for TCAS, GPS and SatCom. (c) A computer recorded data 
from the spectrum analyzer (located underneath the computer). 

4,1.2 Measured Interference Path Loss Results 

Using the method described in the previous section, IPL was measured for several radio receivers on 
six B737-200 and four B747-400 aircraft. The specific systems measured are listed in Table 4.1-2 along 
with the measurement frequencies, and Table 4.1-3 documents the specific aircraft and their nose 
numbers. 

Table 4.1-2: System Measured and Frequency Bands 



Aircraft Systems 


Aircraft Antenna 
Location 


Measurement 

Frequency Range 

(MHz) 


Spectrum 
(MHz) 


VHF-Comm 1 


Top 


116-138 


118-137 


LOCATOR 


Nose (B747) 
Tail (B737) 


108-118 


LOC: 108.1-111.95 
VOR: 108-117.95 


GS 


Nose 


325-340 


328.6-335.4 


TCAS 


Top 


1080-1100 


1090 


GPS (LI) 


Top 


1565-1585 


1575.42 ±2 


SatCom 


Top 


1530-1561 


1545-1559 



80 



Table 4.1-3: B737-200 and B747-400 Aircraft Used for IPL Measurement and Their Nose Numbers 



B737-200 Aircraft 

UAL Nose No. 


B747-400 Aircraft 

UAL Nose No. 


1881 


8173 


1883 


8174 


1879 


8188 


1994 


8186 


1997 




1989 





The following sections report measured IPL data for the aircraft listed. Figures 4.1-6 to 4.1-10 show 
the IPL results for B737 systems, and Figures 4.1-11 to 4.1-16 show the IPL results for B747 systems. 
These plots show IPL versus window/door locations where the transmit antenna radiated. It is important 
to note that the window/door IPL data are similar to the data reported [22], except data in [22] were 
normalized to the 1 -meter path loss measurement. Similar to IPL data in RTCA/DO-199 and RTCA/DO- 
233, data in this document are not normalized to the 1 -meter path loss measurement. 

In addition to the window and door locations, IPL measurements were also conducted at each of the 
seats, including one measurement between two adjacent seats on the left half of two B737 aircraft. As a 
result, each full aircraft (nose number 1989 and 1997) measurement provided approximately 160 
locations (times two for two transmit antenna polarizations) rather than about 36 window and door 
locations. Only the window and door measurements are shown in Figures 4.1-6 to 4.1-10. Statistics of 
the IPL data, including the minimum and the average IPL, are shown in Tables 4.2-1 to 4.2-6. 

Comparing the window/door data against the full aircraft data for these two B737s (nose number 1989 
to 1997), it can be recognized that the window/door measurements capture the minimum IPL for the 
systems on those aircraft. Also, the differences in average IPL values are not significant. This 
comparison validates the common understanding that the minimum IPL occurs at window and door 
locations, at which most measurements on other aircraft were made. 

On these plots, IPL for each receiver system on each aircraft is represented by two traces for the two 
vertical and horizontal polarizations of the transmit antennas. The window locations are simply labeled as 
the n^^ side window starting from the cockpit. The door locations are labeled as "LI" and "L2" for left 
side doors; "SI" and "S2" for right side doors; and "EE" for emergency exits. At the doors, a sweep was 
typically conducted with the transmit antenna scanning along the door seam. A door sweep at LI is 
labeled as "LI Dr Swp". 

It was observed that the IPL for both B737 and B747 aircraft generally had a dip in magnitude when 
the transmitter was located in the vicinity of a door. The magnitude of the dip was significant for GS, 
LOC, VHF Comm and SatCom systems, and it was not observable for TCAS and GPS systems. For GS 
and LOC, the dip in magnitude near the door location did not affect the minimum IPL. On the other 
hand, the magnitude of the dip was about 20 dB for VHF, and about 10 dB for SatCom on B747 aircraft. 
Comparing with SatCom IPL data, GPS IPL data did not show similar behavior, even though both 
systems operate in a similar frequency range. The main difference was that the SatCom antenna was 
mounted in the vicinity of a door. 



81 



B737-200 IPL Results 

120 1 




.."^^P^ 
.^V 



^\ ^■'b^<o<b^<bo,^^^^^i^^ ^^ N^ N* n'* ^^ a> <i> <i> <v<^ <^ T? n> <^ <^ -b^ oN ^^ <g^^ 



Window/Door Location 
Figure 4.1-6: B737-200 LOC/VOR (Tail) interference path loss. Left windows/doors excitation. 

80 



Q. 


O 

C 




B 40 




-1989 V 1989 H 

-1883 V 1883 H 

-1879 V 1879 H 

1997 V 1997 H 

-1994 V 1994 H 

-1881 V 1881 H 



^^N %^^<0<b^<bO,^^^^^^ ^<D ^Qd .<5 <V N^ N^ c^ n> c^ c^ c|^ c^ c^ cf> c^ c^ c^^ oN c^^ c^^^ 



V 



<^ 



„^' 



Window/Door Location 
Figure 4.1-7: B737-200 VHF-1 Comm. (Top) interference path loss. Left windows/doors excitation. 



82 



100 







^N n,^\>^<o<b'K<bo,^^^^^^^ ^.<^ N^ N?> N^ n? a> c^ ^ 0.^ c^ n? 9> 9? n? ^^ oN c^^ c^^^<$ 



Window/Door Location 



.O' 



Figure 4.1-8: B737-200 GS (Nose) interference path loss. Left windows/doors excitation. 



100 



m 
■a 



Q. 
0) 




20 ^ 



<«v^ " ' 






1989V 1989H 

1883V 1883H 

1879V 1879H 

1997 V 1997 H 

1994 V 1994 H 

1881 V 1881 H 



Window/Door Location ^ 



Figure 4.1-9: B737-200 TCAS (Top) interference path loss. Left windows/doors excitation. 



83 



100 1 



B737-200 GPS 
Right Windows Excitation 




^ Right Window/Door Location 

Figure 4.1-lOa: B737-200 GPS interference path loss. Right windows/doors excitation. 



100 



90 



^ 80 

DQ 

•a 



B737-200 GPS 
Left Windows Excitation 




Q. 
V 

o 

c 





70 



60 



50 



40 



30 



-1883 V Left 
-1989 V Left 



1883 H Left 
1989 H Left 



.^"^ .^^ n. ^ tX <D ^ A <b 0> ^Ci ^N ^n. <b ^tX ^ ^^ <^ N^ N^ c^ n> cfV c^ qtx ^ ^fe ^ ^ ^ ^Q ^N ^^ ^^^<5 

^ Left Window/Door Location ^ 

Figure 4.1-lOb: B737-200 GPS interference path loss. Left windows/doors excitation. 



84 



B747-400 IPL Results 



110 




8173V 8173H 

8174V 8174H 

8188V 8188H 

8186 V 8186 H 



Window/Door Location (Lower Deck) 
Figure 4.1-11: B747-400 LOCATOR (Nose) IPL. Lower deck, left windows/doors excitation. 



80 



70 



60 



B747-400 VHF-1 



m 

■a 



HL 50 



^ 40 

V 

o 

c 

« 30 




20 



10 



-AC Pressurized 
8188V 



AC Pressurized 
8188H 



^nO 



.eP 



N^ N^ ^ N^ N^ ^ ^ <S ^ ^ n? 



^^ Right Window/Door Location - Upper Deck 

Figure 4.1-12: B747-400 VHF (Top) interference path loss. Upper deck, right windows/doors excitation. 



85 




8173V 8173H 

8174V 8174H 

8188V 8188H 

8186 V 8186 H 



20 ^ 



n, ^ Ix <D (b A <b O) ^o ,^\ ^q. ,«? 



><p N^ <V ^9> ^O, ^ ^N ^ ^ ^ 



4' 



Window/Door Location - Lower Deck 
Figure 4.1-13: B747-400 GS (Nose) interference path loss. Lower deck, left windows/doors excitation. 




o 

c 50 



40 



30 



20 



-8173 V 8173 H 

-8174 V 8174 H 

-8188 V 8188 H 

8186V 8186H 



Right Window/Door Location - Upper Decic 
Figure 4.1-14: B747-400 TCAS (Top) interference path loss. Upper deck, right windows/doors excitation. 



86 



90 



DQ 

•a 







60 



50 



40 



30 



B747-400 GPS 



3173 V 

3174 V 
3188 V 
3186 V 



8173 H 

8174 H 
8188 H 
8186 H 



20 4 



^ <S ^ ^ c^ 



^^ 



•^ Right Window/Door Location - Upper Decic 

Figure 4.1-15: B747-400 GPS (Top) interference path loss. Upper deck, right windows/doors excitation. 



m 

■a 






90 



80 



70 



60 



50 



40 



30 



20 



B747-SATCOM 


i^^^^^^^^ .. ;;^ 




^^^^-^T'^^^S^ - ; \ :. T'T^^?^^.:.^^^^ 


^^\ ^^^ ^ ^^^^^^^-^-^ 


-^r ~- — r^^'"-^-^-^-^^-^___^"^^^I^^^^;;::>^ .fl' ^-^^^5^^:=-== 


^^^^^l^'rrTrrrrrr: - TTr^. ' ^ 


^"^^<Nv \"-\ Ir " ' ■" " - 


jj^- -'-'.'/ " ' - - ' 


. .-J>^" 


^X ^ w ^^ 






Y 










8173V 8173H 






Q A~7 A \l 0-17/IN 






8186 V 8186 H 













^^ 



ixO 



0/ 'b \X <D (b A % 9> o"^ N^ N^ <V <^ N^ ^^ \^ N> 

Right Window/Door Location - Upper Decl( 
Figure 4.1-16: B747-400 SatCom interference path loss. Upper deck, right windows/doors excitation. 



87 



This phenomenon indicates that the minimum IPL is strongly influenced by the antenna mounting 
locations relative to a door. Variations in IPL by 10 or 20 dB due to antenna installation can be expected 
for any system, not just SatCom and VHF-Comm. 

IPL for VHP on a B747 aircraft was also measured with the aircraft partially pressurized. Figure 4.1- 
12 indicates that by partially pressurizing the passenger cabin, IPL can increase by about 10 dB for a VHP 
system (with the antenna mounted near a door). Thus, pressurizing an aircraft can have a positive effect 
by reducing RF leakage through the door, and can increase the IPL. 

Effects of Closed Cockpit Windows 

In almost all IPL measurements shown in Figures 4.1-6 to 4.1-16, the aircraft cockpit windows were 
often taped closed with aluminum foil. This condition helped to preserve the aircraft interior while these 
aircraft were in storage. Due to various reasons, the measurement team did not have authorization to have 
the foil removed. The concern is whether this configuration could have affected the minimum IPL 
results, especially for the systems with antennas located close to cockpit windows. The side windows 
have built-in shades that help to block light when closed, so they were not taped like the cockpit 
windows. Figure 4.1-16 shows an example of a B737 and B747 aircraft with the cockpit windows 
previously taped and the proximity of the antenna behind the nose radome relative to the cockpit and side 
windows for both airplanes. 

It is important to assess the impact of taped cockpit windows on the minimum path loss value. The 
primary systems of concern are those with antennas in the aircraft nose such as LOG and GS on B747 
aircraft and GS on B737 aircraft. These antennas are much closer to the cockpit windows than those on 
top of the aircraft. 

To address this concern, data from a previous cooperative effort with Delta Airlines (with the technical 
support from EWI) were considered [23]. As a result of the cooperative effort, IPL data were available 
for a B757 aircraft, but without aluminum foil on the cockpit windows. The same procedure used in this 
effort was also used for the B757 IPL measurement. 

In addition to the usual window and door locations, IPL was also measured with a transmit antenna in 
the cockpit radiating out of the cockpit windows. The transmit antenna was scanned around to illuminate 
different parts of the cockpit windows to ensure the maximum coupling mechanisms were captured. The 
results for LOG and GS are shown in Figures 4.1-18 and 4.1-19. Both of these systems have their 
antennas behind the nose radome close to the cockpit. It is important to note that data shown in Figures 
4.1-18 and 4.1-19 are different from the data reported in [23]. Data in [23] have IPL results normalized to 
1 -meter measurements, whereas data in this report do not. 

Figures 4.1-18 and 4.1-19 show that the cockpit IPL data for both LOG and GS were lower than the 
IPL at most other locations. However, they were not the lowest in either case. In fact, they were higher 
than the lowest IPL at the side windows or door by 2-5 dB. 

Data shown in Figures 4.1-18 and 4.1-19 provided the assurance that cockpit IPL data do not impact 
the minimum path loss value for GS and LOG (in the nose) in a significant way. Other window and door 
locations can result in lower IPL. For passenger operated PED interference, cockpit IPL is much less 
relevant since most devices will be located within the passenger cabin. 



88 




B747-400 
LOC & GS 
Antennas 



Figure 4.1-17: (a) B747-400 and (c) B737-200 aircraft with cockpit windows taped. Note the cockpit and side 
window locations relative to the antennas on top and in the nose cone, (b) Horizontally polarized GS and LOC 
antennas were located behind the nose cone. 



100 



B757 LOC 




—• — Vertical 
-□-- Horizontal 



40 



30 



o -o 

o M 



1— 1— 1— 1— C\JC\JC\JC\JC\J 



Aircraft Location 



Figure 4.1-18: B757 LOC window/door path loss. Cockpit windows were not taped. 



89 



100 n 



90 



-S 50 



40 



30 



B757 GS 




- Vertical 



-□-- Horizontal 



.ti C\J 

o o 



coLor--a5i— coLor--a5i— coLor^cD 

1— 1— 1— 1— C\JC\JC\JC\JC\JCOCOCOCOCO 



Window/Door Location 



Figure 4.1-19: B757 GS window/door path loss. Cockpit windows were not taped. 

For a B747 aircraft, Figure 4.1-17(b) shows that the side windows are much closer to the aircraft 
antennas behind the radome than the cockpit windows. Comparing the distance from the cockpit 
windows to the nose or top antennas, Figure 4.1-17 shows that the upper deck windows are closer to the 
top antennas, and the lower deck windows are closer to the nose antennas. Based on B757 cockpit data 
shown in Figures 4.1-18 and 4.1-19, it is expected that B747 cockpit IPL will not affect (lower) the 
minimum IPL significantly. 

4.2 Other Interference Path Loss Data 

In addition to the data previously presented, there are other IPL data previously reported in various 
documents. These documents include RTCA/DO-199 [2], DO-233 [3], a Veda [5] report, including those 
from the cooperative agreement between NASA and Delta Airlines [23]. Most of these data were 
previously summarized in the report on interference effects of cellular phones to aircraft radio-navigation 
receivers [1]. For completeness, they are again reported in Tables 4.2-1 to 4.2-7 along with the recently- 
measured B747 and B737 IPL data. 

In RTCA/DO-199 (Appendix A), most reported papers used the same definition for IPL as shown in 
Eq. 4.1-1, but with a correction for transmit antenna gain. Namely, 



PLF = (Tx Power in dBm) - (Rx Power in dBm) + (Tx Antenna Gain in dB), 



(Eq. 4.2-1) 



where 



PLF is Path Loss Factor, and 

Tx and Rx are Transmit and Receive (Antennas), respectively. 



90 



There were also test papers in RTCA/DO-199 with PLF calculated without the correction applied 
(paper SC156-110), and the transmit antenna gain factors were not provided. In these cases, the path loss 
definition is the same as in Eq. 4.1-1. 

Boeing 757 path loss data from papers RTCA/DO-199 SC156-26, -65 and -186 for VOR, LOG, VHP 
Comm. and GS are not reported in Tables 4.2-1 to 4.2-7. These papers defined transmit power in a way 
not directly comparable with definitions used in this document, RTCA/DO-233, and the remaining papers 
in RTCA/DO-199. Data from these papers resulted in unusually low path loss values and are excluded 
from the minimum IPL estimation in Table 4.3-1 and the interference safety margin calculations in 
Section 5. 

In RTCA/DO-233, PLF calculations "may" include Tx antenna gain. Antenna factors were given for a 
dipole antenna used but not for other transmit antennas. 

The main difference between the path loss definition in this document and the definition used in parts 
of RTCA/DO-199 and RTCA/DO-233 is whether the transmit antenna's free-space antenna factors are 
included in the path loss data provided. In this document, it is assumed that the environment is far from 
free space and that free-space antenna factors are not valid correction factors. The true transmit antenna 
factors are not known, and are not included in the path loss calculations. However, free-space antenna 
factors for the antennas used are provided in Table 4.1-1. 

In Tables 4.2-1 to 4.2-7, IPL was reported for LOC, GS, VHP Comm., SatCom, TCAS, and GPS. 
Data were grouped into large, medium, and small aircraft categories. For each aircraft measured, the 
minimum IPL (MIPL), the average IPL and the standard deviation (StDev) were reported. The new B747 
and B737 data in these tables were computed from Figures 4.1-6 to 4.1-16. They were computed from 
the combined data for both vertical and horizontal polarizations. 

The number of measurement points and measurement frequency range were also reported when 
available. The number of measurement points was often reported as a number times 2, i.e. "26x2'\ This 
notation indicated that both transmit antenna polarizations, vertical and horizontal, were used at each 
measurement location, effectively doubling the number of data points. Thus, "26x2" indicated 
measurements were taken at 26 locations, with vertical and horizontal polarized source antenna, resulting 
in 52 data points. 

The statistics of the MIPL for each large, medium and small aircraft category were also reported. In 
addition, statistics of the MIPL calculated using ALL available data were shown at the end of each table 
and again in Table 4.3-1. These statistics include the lowest MIPL and the average MIPL for the safety 
margin calculations in Section 5. 



91 



Table 4.2-1: LOC IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min (MIPL) 


Average 


StDev 



Large Aircraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI/NASA) 
^ B747 8188 (UAL/EWI/NASA) 
^ B747 8186 (UAL/EWI/NASA) 
B747 (DO-233) 
B747 (EWI/UAL) 
DCIO (DO-199) 
Lion (DO-233) 

Column Minimum 

Column Average 

Column Maximum 

Medium Aircraft 

^ B737 1989 Windows (UAL/EWI/NASA) 

^ B737 1989 Full (UAL/EWI/NASA) 

^ B737 1883 (UAL/EWI/NASA) 

^ B737 1879 (UAL/EWI/NASA) 

^ B737 1997 (UAL/EWI/NASA) 

^ B737 1994 (UAL/EWI/NASA) 

^ B737 1881 (UAL/EWI/NASA) 

B737 (DO-233) 

B757 (DO-233) 

B757 (Delta/EWI/NASA) 

B727 -a (DO-199) 

B727 -b (DO-199) 

B727 (RTCA/SC-177) 

A320 (DO-233) 

A320 (Aerospatiale) 

Column Minimum 

Column Average 

Column Maximum 

Small Aircraft 

Canadair RJ (Delta/EWI/NASA) 
Emb 120 (Delta/EWI/NASA) 
ATR72 (Delta/EWI/NASA) 

Column Minimum 
Column Average 

Column Maximum 



51.8 


68.8 


9.4 


26x2 


108-118 


62.7 


82.3 


10.9 


26x2 


108-118 


55.0 


77.7 


11.6 


26x2 


108-118 


58.9 


77.0 


10.6 


26x2 


108-118 


64.8 


93.9 


12.7 






55.0 


61.0 


2.0 


38 




82.0 


91.0 




10 


108 


60.7 


85.2 


9.4 






51.8 


61.0 








61.4 


79.6 








82.0 


93.9 








65.0 


78.1 


1.1 


36x2 


108-118 


65.0 


81.7 


5.6 


156x2 


108-118 


56.5 


73.0 


9.8 


36x2 


108-118 


61.8 


77.5 


1.1 


36x2 


108-118 


74.2 


87.3 


6.2 


36x2 


108-118 


62.6 


78.5 


7.9 


36x2 


108-118 


67.0 


78.6 


6.0 


36x2 


108-118 


72.7 


90.7 


8.8 






51.5 


86.1 


11.4 






56.1 


75.3 


10.2 


52x2 




63.0 


67.0 




6 


108-112 


35.0 


53.0 




86 


108-112 


72.0 


90.0 








48.8 


85.7 


14.8 






54.0 


75.0 








35.0 


53.0 








60.3 


78.5 








74.2 


90.7 








57.9 


71.6 


6.6 


14x2 




41.8 


56.3 


4.5 


11x2 




63.9 


72.1 


4.2 


25x2 




41.8 


56.3 








54.5 


66.7 








63.9 


72.1 









92 



Table 4.2-1: Concluded 



All Aircraft Column Minimum 
All Aircraft Column Average 
All Aircraft Column Maximum 
All Aircraft Standard Deviation 



35.0 


53.0 


60.0 


77.5 


82.0 


93.9 


10.0 


10.4 



93 



Table 4.2-2: VHF Comm IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min (MIPL) 


Average 


StDev 



V 

^ 
^ 
^ 
^ 



Large Aircraft 

B747 8173 (UAL/EWI/NASA) 
B747 8174 (UAL/EWI/NASA) 
B747 8188 (UAL/EWI/NASA) 
B747 8186 (UAL/EWI/NASA) 
B747 8188 (UAL/EWI/NASA) 

(AC Pressurized) 
B747 -VHFl (DO-233) 
B747 -VHF2 (DO-233) 
B747 -VHF3 (DO-233) 
DC 10 (DO-199) 
Lion -VHFl (DO-233) 
L1011-VHF2 (DO-233) 
L1011-VHF3 (DO-233) 

Column Minimum 
Column Average 

Column Maximum 



V 


Medium Aircraft 

B737 1989 (UAL/EWI/NASA) 


^ 


B737 1883 (UAL/EWI/NASA) 


^ 


B737 1879 (UAL/EWI/NASA) 


^ 


B737 1997 Windows (UAL/EWI/NASA) 


^ 


B737 1997 Full (UAL/EWI/NASA) 


^ 


B737 1994 (UAL/EWI/NASA) 


^ 


B737 1881 (UAL/EWI/NASA) 



B737 -VHFl (DO-233) 
B737 -VHF2 (DO-233) 
B737 -VHF3 (DO-233) 
B757 -VHFl (DO-233) 
B757 -VHF2 (DO-233) 
B757 -VHF3 (DO-233) 
B757-VHF-Left (Delta/EWI/NASA) 
B757-VHF-Right (Delta/EWI/NASA) 
B757-VHF-Center (Delta/EWI/NASA) 
B727N40 -a (DO-199) 
B727N40-b (DO-199) 
B727N40-C (DO-199) 



31.5 


53.9 


7.7 


21x2 


116-138 


32.3 


56.3 


6.7 


21x2 


116-138 


35.3 


58.9 


6.6 


21x2 


116-138 


35.3 


59.5 


7.9 


21x2 


116-138 


43.2 


61.5 


5.9 


21x2 


116-138 


40.5 


79.2 


12.0 






63.2 


86.2 


10.8 






71.5 


92.9 


7.4 






63.0 


80.0 




45 


117-137 


56.2 


72.9 


6.1 






62.2 


77.2 


4.2 






31,5 


53,9 








48,6 


70,8 








7L5 


92,9 








52.3 


61.9 


5.2 


36x2 


116-138 


46.8 


59.3 


5.2 


36x2 


116-138 


50.1 


61.6 


4.7 


36x2 


116-138 


51.5 


61.9 


5.8 


36x2 


116-138 


51.5 


65.8 


4.3 


173x2 


116-138 


48.6 


63.5 


5.1 


36x2 


116-138 


52.6 


61.2 


4.5 


36x2 


116-138 


52.9 


69.0 


7.6 






58.4 


74.2 


9.3 






53.2 


76.2 


9.6 






49.7 


72.9 


9.8 






38.0 


64.7 


8.7 






53.0 


79.3 


8.7 






36.3 


52.8 


7.4 


56x2 




49.3 


60.6 


6.2 


38x2 




50.3 


64.0 


6.7 


55x2 




67.0 


71.0 




6 


118-135 


44.0 


53.0 




49 


118-135 


76.0 


80.0 




6 


109 



94 



Table 4.2-2: Concluded 



MD80-VHF1 (DO-233) 


57.2 


74.5 


9.2 




MD80-VHF2 (DO-233) 


64.9 


81.7 


10.0 




MD80-VHF3 (DO-233) 


55.2 


81.7 


13.3 




A320 -VHFl (DO-233) 


51.5 


70.0 


8.4 




A320 -VHF2 (DO-233) 


62.1 


77.6 


6.7 




A320 -VHF3 (DO-233) 


55.6 


76.2 


7.4 




Column Minimum 


36.3 


52.8 






Column Average 


53.1 


68.6 






Column Maximum 


76.0 


81.7 






Small Aircraft 










CRJ VHF-L (Delta/EWI/NASA) 


36.7 


53.7 


7.6 


14x2 


CRJ VHF-R (Delta/EWI/NASA) 


50.9 


62.3 


6.0 


14x2 


Emb 120 -VHF-L (Delta/EWI/NASA) 


28.7 


47.0 


7.3 


12x2 


Emb 120 -VHF-R (Delta/EWI/NASA) 


45.0 


53.5 


3.7 


11x2 


ATR72- VHF-L (Delta/EWI/NASA) 


48.4 


61.3 


8.2 


13x2 


ATR72- VHF-R (Delta/EWI/NASA) 


43.5 


60.0 


6.3 


26x2 


Column Minimum 


28.7 


47.0 






Column Average 


42.2 


56.3 






Column Maximum 


50.9 


62.3 






All Aircraft Column Minimum 


28.7 


47.0 






All Aircraft Column Average 


50.4 


67.4 






All Aircraft Column Maximum 


76.0 


92.9 






All Aircraft Standard Deviation 


10.9 


10.6 







95 



Table 4.2-3: VOR IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min 
(MIPL) 


Average 


StDev 



Large Aircraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI/NASA) 
^ B747 8188 (UAL/EWI/NASA) 
^ B747 8186 (UAL/EWI/NASA) 
B747 (DO-233) 
B747 (EWI/UAL) 
DC 10 (DO-199) 
Lion (DO-233) 

Column Minimum 

Column Average 

Column Maximum 

Medium Aircraft 

^ B737 1989 Windows (UAL/EWI/NASA) 
^ B737 1989 Full (UAL/EWI/NASA) 



B737 1883 (UAL/EWI/NASA) 
B737 1879 (UAL/EWI/NASA) 
B737 1997 (UAL/EWI/NASA) 
B737 1994 (UAL/EWI/NASA) 
B737 1881 (UAL/EWI/NASA) 
B737 (DO-233) 
B757 (DO-233) 
B757 (Delta/EWI/NASA) 
B727-a (DO-199) 
B727 -b (DO-199) 
B727-C (DO-199) 
B727 (RTCA/SC-177) 
CV-580 (Veda/FAA) 
MD80 (DO-233) 
A320 (DO-233) 
A320 (Aerospatiale) 

Column Minimum 
Column Average 

Column Maximum 



51.8 


68.8 


9.4 


26x2 


108-118 


62.7 


82.3 


10.9 


26x2 


108-118 


55.0 


11.1 


11.6 


26x2 


108-118 


58.9 


11.0 


10.6 


26x2 


108-118 


84.7 


105.0 


5.1 






76.0 


80.0 


3.0 


8 




80.0 


89.0 




20 


113-117 


70.3 


79.0 


2.0 






Sh8 


68,8 








67,4 


82,4 








84 J 


105,0 








65.0 


78.1 


1.1 


36x2 


108-118 


65.0 


81.7 


5.6 


156x2 


108-118 


56.5 


73.0 


9.8 


36x2 


108-118 


61.8 


77.5 


7.7 


36x2 


108-118 


74.2 


87.3 


6.2 


36x2 


108-118 


62.6 


78.5 


7.9 


36x2 


108-118 


67.0 


78.6 


6.0 


36x2 


108-118 


76.0 


90.0 


5.0 






49.9 


90.7 


9.9 






46.7 


65.8 


6.8 


56x2 




70.0 


74.0 




6 


112-117 


30.0 


56.0 




86 


112-117 


71.0 


76.0 




6 


109-120 


75.0 


90.0 








45.0 










66.2 


87.8 


9.4 






65.0 


91.9 


8.7 






59.0 


84.0 








30,0 


56,0 








61,4 


80,1 








76,0 


91,9 









96 



Table 4.2-3: Concluded 



Small Aircraft 

Canadair RJ (Delta/EWI/NASA) 
Emb 120 (Delta/EWI/NASA) 
ATR72 (Delta/EWI/NASA) 

Column Minimum 
Column Average 

Column Maximum 

All Aircraft Column Minimum 
All Aircraft Column Average 
All Aircraft Column Maximum 
All Aircraft Standard Deviation 



57.9 


71.6 


6.6 


14x2 


41.8 


56.3 


4.5 


11x2 


63.9 


72.1 


4.2 


25x2 


41.8 


56.3 






54.5 


66.7 






63.9 


72.1 






30.0 


56.0 






62.4 


79.3 






84,7 


105,0 






12,2 


10.6 







97 



Table 4.2-4: GS IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) 
(dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min 
(MIPL) 


Average 


StDev 



Large Aircraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI/NASA) 
^ B747 8188 (UAL/EWI/NASA) 
^ B747 8186 (UAL/EWI/NASA) 
B747 (DO-233) 
B747 (EWI/UAL) 
DCIO (DO-199) 
Lion (DO-233) 

Column Minimum 

Column Average 

Column Maximum 

Medium Aircraft 

^ B737 1989 (UAL/EWI/NASA) 

^ B737 1883 (UAL/EWI/NASA) 

^ B737 1879 (UAL/EWI/NASA) 

^ B737 1997 Windows (UAL/EWI/NASA) 

^ B737 1997 Full (UAL/EWI/NASA) 

^ B737 1994 (UAL/EWI/NASA) 

^ B737 1881 (UAL/EWI/NASA) 

B737 (DO-233) 

B757 (DO-233) 

B757 (Delta/EWI/NASA) 

B727 (RTCA/SC-177) 

B727 (DO-199) 

CV-580 (Veda/FAA) 

MD80 (DO-233) 

A320 (DO-233) 

A320 (Aerospatiale) 

Column Minimum 

Column Average 

Column Maximum 

Small Aircraft 

Canadair RJ (Deltay^WI/NASA) 

Emb 120 (Delta/EWI/NASA) 

ATR72 

Column Minimum 

Column Average 

Column Maximum 



49.3 


67.6 


8.4 


26x2 


325-340 


51.0 


69.6 


9.3 


26x2 


325-340 


49.3 


68.8 


7.9 


26x2 


325-340 


48.9 


66.1 


8.5 


26x2 


325-340 


54.6 


86.2 


14.1 






53.0 


71.0 


8.0 


36 




77.0 


91.0 




24 


329-335 


64.4 


82.6 


8.1 






48,9 


66,1 








55,9 


75,4 








77,0 


91,0 








58.9 


70.1 


5.0 


36x2 


325-340 


60.2 


75.1 


6.5 


36x2 


325-340 


59.7 


75.4 


5.5 


36x2 


325-340 


61.7 


72.2 


5.2 


36x2 


325-340 


61.7 


73.3 


4.3 


169x2 


325-340 


61.4 


73.9 


6.5 


36x2 


325-340 


59.5 


72.2 


5.7 


36x2 


325-340 


68.8 


83.1 


4.9 






57.5 


83.0 


9.9 






58.9 


72.1 


6.0 


53x2 




68.0 


83.0 








68.0 


76.0 




12 


328 


64.0 










63.5 


85.4 


11.0 






64.6 


84.2 


10.0 






56.0 


70.0 








56,0 


70,0 








62,0 


76,6 








68,8 


85,4 








51.6 


59.7 


3.2 


14x2 




46.2 


51.5 


2.3 


10x2 




57.5 


68.0 


5.4 


26x2 




46,2 


57.5 








51,8 


59,7 








57,5 


68,0 









98 



Table 4.2-4: Concluded 



All Aircraft Column Minimum 
All Aircraft Column Average 
All Aircraft Column Maximum 
All Aircraft Standard Deviation 



46.2 


51.5 


59.1 


74.3 


77.0 


91.0 


7.2 


8.8 



99 



Table 4.2-5: TCAS IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min 
(MIPL) 


Average 


StDev 



Large Aircraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI /NASA) 
^ B747 8188 (UAL/EWI /NASA) 
^ B747 8186 (UAL/EWI /NASA) 

Column Minimum 
Column Average 

Column Maximum 

Medium Aircraft 

^ B737 1989 (UAL/EWI /NASA) 

^ B737 1883 (UAL/EWI/NASA) 

^ B737 1879 (UAL/EWI/NASA) 

^ B737 1997 Windows (UAL/EWI /NASA) 

^ B737 1997 Full (UAL/EWI /NASA) 

^ B737 1994 (UAL/EWI /NASA) 

^ B737 1881 (UAL/EWI/NASA) 

B757 (DO-233) 

B757-TCAS-Top (Deltay^WI /NASA) 

B757-TCAS-Bottom (Delta/EWI /NASA) 

A320 -TCAS-T (DO-233) 

A320 -TCAS-B (DO-233) 

A320 (Aerospatiale) 

Column Minimum 

Column Average 

Column Maximum 

Small Aircraft 

CRJ TCAS-Top(Delta/EWI /NASA) 
CRJ TCAS-Bottom(Deltay^WI /NASA) 
Emb 120 -TCAS-Top (Deltay^WI /NASA) 
Emb 120 -TCAS-Bottom (Delta/EWI /NASA) 
ATR72- TCAS-Top(Delta/EWI /NASA) 
ATR72- TCAS-Bottom(Delta/EWI /NASA) 

Column Minimum 
Column Average 

Column Maximum 

All Aircraft Column Minimum 
All Aircraft Column Average 
All Aircraft Column Maximum 
All Aircraft Standard Deviation 



63.2 


69.9 


4.4 


21x2 


1080-1100 


61.7 


67.3 


3.3 


21x2 


1080-1100 


63.3 


68.6 


2.3 


21x2 


1080-1100 


64.2 


71.0 


3 


21x2 


1080-1100 


61.7 


67.3 








63.1 


69.2 








64.2 


71.0 








53.0 


66.1 


4.4 


36x2 


1080-1100 


52.8 


64.8 


4.3 


36x2 


1080-1100 


55.8 


67.6 


4.4 


36x2 


1080-1100 


54.3 


68.3 


4.4 


36x2 


1080-1100 


54.3 


70.9 


3.8 


179x2 


1080-1100 


56.6 


69.3 


4.2 


36x2 


1080-1100 


56.3 


69.0 


4.5 


36x2 


1080-1100 


69.1 


83.3 


7.3 






58.6 


71.5 


6.9 


55x2 




57.6 


75.0 


7.7 


53x2 




54.8 


74.6 


11.3 






63.0 


78.5 


7.1 






52.8 


64.8 








57.2 


71.6 








69.1 


83.3 








53.1 


59.2 


4 


14x2 




54.7 


61.5 


3.3 


14x2 




50.7 


57.6 


4.5 


11x2 




48.2 


59.7 


5.8 


11x2 




48.2 


57.6 








51.7 


59.5 








54.7 


61.5 








48.2 


57.6 








57.3 


68.7 








69.1 


83.3 








5.3 


6.4 









100 



Table 4.2-6: SatCom IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range (MHz) 


Min (MIPL) 


Average 


StDev 



Large Aircraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI/NASA) 

V B747 8188 (UAL/EWI/NASA) 

V B747 8186 (UAL/EWI/NASA) 
B747 (DO-233) 

Column Minimum 

Column Average 

Column Maximum 

Column Standard Deviation 



52.1 


IQ.l 


18.6 


21x2 


51.5 


70.1 


18.6 


21x2 


53.6 


65.8 


12.2 


21x2 


55.5 


70.2 


14.7 


21x2 


87.0 


96.8 


5.0 




51.5 


65.8 






59.9 


74.7 






87.0 


96.8 






15.2 


12.5 







101 



Table 4.2-7: GPS IPL 



New 
Data 


Aircraft & Model 


Interference Path Loss (IPL) (dB) 


No. of 
Meas. 


Test Freq. 
Range 
(MHz) 


Min 
(MIPL) 


Average 


StDev 



Large Aicraft 

^ B747 8173 (UAL/EWI/NASA) 
^ B747 8174 (UAL/EWI/NASA) 
^ B747 8188 (UAL/EWI/NASA) 
^ B747 8186 (UAL/EWI/NASA) 

Column Minimum 
Column Average 

Column Maximum 

Medium Aircraft 

^ B737 1989 (UAL/EWI/NASA) 
^ B737 1883 (UAL/EWI/NASA) 
^ B737 1879 (UAL/EWI/NASA) 
^ B737 1997 (UAL/EWI/NASA) 
^ B737 1994 (UAL/EWI/NASA) 
^ B737 1881 (UAL/EWI/NASA) 
CV-580 (Veda/FAA) 
B727 N40 (DO-199) 

Column Minimum 

Column Average 

Column Maximum 

Small Aircraft 

GulfG4(DO-233) 
CRJ (Delta/EWI/NASA) 

Column Minimum 
Column Average 

Column Maximum 

All Aircraft Column Minimum 
All Aircraft Column Average 
All Aircraft Column Maximum 
All Aircraft Standard Deviation 



65.7 


73.5 


4.0 


21x2 


1565-1585 


66.3 


72.9 


3.3 


21x2 


1565-1585 


64.7 


70.6 


2.9 


21x2 


1565-1585 


66.3 


74.0 


3.5 


21x2 


1565-1585 


64.7 


70.6 








65.8 


72.8 








66.3 


74.0 








64.9 


75.0 


4.0 


36x2 


1565-1585 


64.0 


76.0 


5.3 


76x2 


1565-1585 


71.2 


77.1 


3.9 


33x2 


1565-1585 


68.8 


74.5 


2.7 


34x2 


1565-1585 


67.4 


74.4 


3.9 


34x2 


1565-1585 


67.2 


73.0 


3.5 


33x2 


1565-1585 


41.0 










71.0 


77.0 




12 


1575 


41.0 


73.0 








64.4 


75.3 








71.2 


77.1 








82.4 


91.4 


5.7 






43.2 


53.5 


6.1 


14x2 




43.2 


53.5 








62.8 


72.5 








82.4 


91.4 








41.0 


53.5 








64.6 


74.1 








82,4 


91.4 








10.6 


8.0 









102 



4.3 Summary of Minimum Interference Path Loss Data 

Table 4.3-1 summarizes the MIPL shown in the tables in Section 4.2. Data in this table were taken 
from the "All Aircraft" summary rows at the end of each table. In this table, the minimum MIPL values 
displayed are the lowest MIPL of all aircraft. Likewise, the average MIPL values displayed are the 
average of the MIPL of all aircraft. The minimum MIPL and the average MIPL will be used in the later 
calculations for interference safety margins. The maximum MIPL and the StDev of the MIPL of all 
aircraft are also shown. The standard deviations were calculated without assigning additional weight to 
any specific aircraft model or number of measurement points. 

As observed from the table, there can be a large difference in dB between the maximum MIPL and the 
minimum MIPL. MIPL can vary between 35 dB to 82 dB for LOG and between 30 dB to 84.7 dB for 
VOR. TCAS system has the smallest MIPL range, 48.2 dB to 69.1 dB, and the lowest MIPL standard 
deviation value of 5.3 dB. 



Table 4.3-1: Summary of Aircraft Minimum IPL (MIPL) 





Min MIPL 


Ave MIPL 


Max MIPL 


StDev 




(dB) 


(dB) 


(dB) 


(dB) 


LOC 


35.0 


60.0 


82.0 


10.0 


VOR 


30.0 


62.4 


84.7 


12.2 


VHF 


28.7 


50.4 


76.0 


10.9 


GS 


46.2 


59.1 


77.0 


7.2 


TCAS 


48.2 


57.3 


69.1 


5.3 


SatCom 


51.5 


59.9 


87.0 


15.2 


GPS 


41.0 


64.6 


82.4 


10.6 



5 Interference Analysis 

In this section, receiver susceptibility thresholds are discussed, and the measured interference 
thresholds are summarized from RTCA/DO-199. In addition, safety margins are calculated from the 
interference susceptibility thresholds, the path loss data in Section 4, and the emissions from WLAN 
devices and two-way radios. 

5.1 Published Receiver Susceptibility 

Of the three elements required for risk assessment (WLAN/PED/two-way radio emission; aircraft IPL; 
and receiver interference threshold), receiver interference threshold (to FED interfering signal) is the one 



103 



element with the least amount of available data. RTCA/DO-199 and RTCA/DO-233 provide the most 
information on the subject. However, the amount of data available is far from enough to provide 
confidence in the figures provided. Except for GPS, the ICAO Annex 10, Vol.1 [24] and receiver MOPS 
did not properly address the in-band, on-channel interference. Spurious signals from PEDs and WLAN 
devices were too low to cause other interference, such as desensitization, addressed in these documents. 

5.1.1 RTCA/DO'233 

For LOG, RTGA/DO-233 sets four different interference thresholds for in-band, on-channel 
interference. Signal-to-Interference (S/I) ratio for the four interference types can vary between 7 dB to as 
much as 46 dB depending upon the frequency spacing between the GW interference signal from the 90 
Hz or 150 Hz ILS sidebands of the LOG carrier. In addition, a modulated interference signal may result 
in a different interference threshold than GW interference. Additional information is documented in [3] 
and in [1]. 

RTGA/DO-233 did not provide similar guidance for other systems such as VOR or GS. And unlike 
RTGA/DO-199, RTGA/DO-233 did not provide data to support their findings and recommendations 
concerning receiver interference thresholds. 

5.1.2 RTCA/D0'199 

RTGA/DO-199 is the only publicly available document that provided results from testing of 
receiver interference thresholds. In RTGA/DO-199, receiver interference levels along with test signal 
strengths were documented in the form of tables and charts, from which relevant threshold data for LOG, 
GS, VOR, TGAS, VHF-Gom and SatGom were extracted. For a GW interference signal, the official S/I 
ratios were chosen from the typical values, which were valid across most of the channel bandwidth. 
However, when the interfering signal was such that it mixed with the local carrier to produce a frequency 
close to the receiver's side band, susceptibility notches could occur. Test results show the 5/7 ratio can be 
as high as 38 dB for LOG, 35 dB for GS and 46 dB for VOR. Theoretical analysis was also conducted 
and presented for LOG and VOR. 

For GW interference, the disruption threshold tends to vary along with the signal level in such a 
way that the S/I ratio stays constant. As a result, the disruption threshold can only be determined if the 
test signal is known. In RTGA/DO-199, the test signals were set equal to the minimum desired signals at 
the receivers. These signals were calculated from the minimum desired external field environments 
within the coverage airspace assuming an isotropic, lossless antenna, and fixed values of cable losses. 
The minimum desired external field environments were taken from several sources. The sources 
included the IGAO Annex 10, Vol.1, and FAA National Orders, and others depending on the system 
under consideration. Additional details on the desired signal strength calculations and the interference 
criteria unique to each system can be found in RTGA/DO-199. 

According to RTGA/DO-199, it was very difficult to maintain signal lock at the susceptibility notches to 
cause undetected interference even if it was intended. The official thresholds were selected, therefore, by 
ignoring narrowband notches. Table 5.1-1 summarizes the test signal level used, the official disruption 
threshold, along with the unofficial disruption threshold at the susceptibility notches. The underlined data 
in this table were used in the safety margin calculations in Section 5.2. 



104 



Table 5.1-1: RTCA/DO-199 Interference Thresholds 





LOC 


VOR 


GS 


VHF 


GPS 


MLS 


Desired Signal at Receiver (dBm) 


-88 


-97 


-78 


-89 






Typical Interference Level (dBm) 

Signal/Inteference (S/I) Ratio (dB) 


-104 

16 


-110 

13 


-93 

15 


-107 

18 


-126.5* 


-62 


Minimum Interference Level (dBm) 
(at notches) 

Signal/Interference ratio (dB) 


-127 
39 


-143 

46 


-113 

35 


-107 

18 






Theoretical Thresholds (dBm) 

Theoretical S/I Ratio (dB) 


-130 

42 


-148 

51 


-120 

42 









* For GPS, -126.5 dBm minimum interference level is required in GPS receiver MOPS such as DO-208 and DO- 
229B. DO-199 provides -130 dBm interference level for GPS. 

For GPS, the interference threshold w^as very wqW defined and w^as consistent across various standards, 
Technical Standard Orders (TSOs) and receiver MOPS for airborne navigation equipment. These 
documents provided the minimum performance standards for stand-alone, satellite-based and ground- 
based GPS systems and sensors. A few of these documents include: ITU-R M.1477 [25], RTCA/DO- 
235A [26], RTCA/DO-229B [27], RTCA/DO-253A [28], RTCA/DO-228 [29], and RTCA/DO-208 [30]. 

These documents show that the lowest interference threshold is -126.5 dBm for a GPS system in 
acquisition mode with CW interference or signals with bandwidth up to 700 Hz. This threshold was 
specified at the output of a passive antenna, or at the output of an active antenna, but before the pre- 
amplifier stage. Thus, the active GPS antenna pre-amplification gain must be accounted for in the path 
loss value in order to use the -126.5 dBm threshold value. 

5.2 Safety Margin Calculations 

Knowing device emission "A", aircraft minimum path loss "-B", and receiver susceptibility threshold 
"C", safety margin can be computed using 

Safety Margin = C-(A +B) 

This section first calculates the interference signal strength at the receiver's antenna port (A -i-B). 
Safety margin can then be computed with the knowledge of "C". 

Applying the minimum and the average values of MIPL ("-B") in Table 4.3-1 to the emission data 
("A") in Table 3.6-1, the resulting interference signals at the receiver ("A-i-B") are shown in Table 5.2-1. 
Due to the large range of IPL "-B" values, the results of the calculation (A-i-B) are presented with only the 
maximum and the average values that are calculated from the minimum and the average path loss "-B" 
values. 



105 



Table 5.2-1: Interference Signal Strength at Receiver's Antenna Port (A+B). Maximum and Average values in 

dBm 





802.11b 


Bluetooth 


802,11a 


FRS/GMRS 
Radio 


Laptops/ 
PDA 


LOC (Max/Ave) 


-113.2/-138.2 


-101.8/-126.8 


-109.2/-134.2 


-114.3/-139.3 


-103/-128 


VOR (Max/Ave) 


-108.2/-140.6 


-96.8/-129.2 


-104.2/-136.6 


-109.3/-141.7 


-98.0/-130.4 


VHF(*) (Max/Ave) 


-106.9/-128.6 


-95.5/-117.2 


-102.9/-124.6 


-108/-129.7 


-96.7/-118.4 


GS (Max/Ave) 


-121.9/-134.8 


-123.4/-136.3 


-118/-130.9 


-74.7/-87.6 


-104.9/-117.8 


TCAS (Max/Ave) 


-113.5/-122.6 


-97.9/-107 


-105.9/-115 


-91.7/-100.8 


-93.9/-103 


GPS (Max/Ave) 


-108.7/-132.3 


-122.7/-146.3 


-106.2/-129.8 


-98.0/-121.6 


-96.8/-120.4 


MLS (Max/Ave) 


-155.7/-161.7 


-156.2/-162.2 


-130/- 136 


-111/-117 


-155/-161 



(*) Emission data were not collected in the VHP band (118 - 137 MHz). For this calculation, the VHP band 



maximum emission was assumed to be the same as in Band 1 (105 
bands. 



120 MHz), which covered LOC and VOR 



Comparing the maximum and the average signal strength at the receivers, (A+B), in Table 5.2-1 to the 
typical and the minimum susceptibility thresholds in Table 5.1-1, safety margins can be calculated. The 
result for each system is a 2x2 matrix. Deciding w^hich element of the safety margin matrix to use 
depends upon w^hether the maximum or the average value for (A+B) w^as used, and on w^hether the typical 
or the minimum interference threshold was used. In the cases where there was only one value for 
interference threshold, such as GPS, the safety margin results are 2x1 matrices. 

Tables 5.2-2 to 5.2-7 report the results of the calculation with the safety margin results highlighted in 
bold for each combination of WLAN/radio device, MIPL, and interference threshold values. The 
calculations were conducted for LOC, VOR, VHP Comm, GS, GPS and MLS. To determine safety 
margin using the tables, one simply locates the right combinations of WLAN/PED/Radio devices, MIPL 
values, and interference thresholds on the tables. Thus, for LOC, the combination of a 802.1 lb WLAN 
device, a minimum MIPL (resulting in the interference signal at receiver of -1 13.2 dB), and a minimum 
LOC interference threshold (-127 dBm) results in -13.8 dB safety margin. A large positive safety margin 
is desirable, whereas a large negative safety margin indicates a possibility of interference. 

Safety margin calculations for TCAS and SatCom were not possible due to lack of interference 
threshold data. However, IPL and WLAN/radio device emissions reported can be used in future 
calculations once the interference thresholds are defined. 



106 



Table 5.2-2: LOG Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds 





802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Interference Signal 
at Receiver (dBm) = 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


-113.2 


-138.2 


-101.8 


-126.8 


-109.2 


-134.2 


-114.3 


-139.3 


-103.0 


-128.0 


LOC Interference 












Threshold 












Minimum (dBm) -727 


-13.8 11.2 


-25.2 -0.2 


-17.8 7.2 


-12.7 12.3 


-24.0 1.0 


Typical (dBm) -104 


9.2 34.2 


-2.2 22.8 


5.2 30.2 


10.3 35.3 


-1.0 24.0 



Table 5.2-3: VOR Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds 





802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Interference Signal 
at Receiver (dBm) = 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


-108.2 


-140.6 


-96.8 


-729.2 


-104.2 


-136.6 


-109.3 


-141.7 


-98.0 


-130.4 


VOR Interference 












Threshold 












Minimum (dBm) -143 


-34.8 -2.4 


-46.2 -13.8 


-38.8 -6.4 


-33.7 -1.3 


-45.0 -12.6 


Typical (dBm) -110 


-1.8 30.6 


-13.2 19.2 


-5.8 26.6 


-0.7 31.7 


-12.0 20.4 



Table 5.2-4: VHF Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds (see note below table) 



Interference Signal 
at Receiver (dBm) = 


802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


-106.9 


-128.6 


-95.5 


-117.2 


-102.9 


-124.6 


-108.0 


-129.7 


-96.7 


-118.4 


VHF 

Interference 

Threshold 

(dBm) 


-0.1 21.6 


-11.5 10.2 


-4.1 17.6 


1.0 22.7 


-10.3 11.4 



Note: RF emission data were not collected in the VHF band (Band 1 does not cover the VHF band). Since the 
frequency band are close (105 - 120 MHz for Band 1 and 1 18 - 137 MHz for VHF band), it is assumed for this 
calculation that the emission in the VHF band is equal to the emissions in the Band 1. 



107 



Table 5.2-5: GS Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds 





802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Min 


Ave 


Interference Signal 
at Receiver (dBm) = 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


MIPL 


-727.9 


-134.8 


-123.4 


-136.3 


-118.0 


-130.9 


-74.7 


-87.6 


-104.9 


-117.8 


GS Interference 












Threshold 












Minimum (dBm) -113 


8.9 21.8 


10.4 23.3 


5.0 17.9 


-38.3 -25.4 


-8.1 4.8 


Typical (dBm) -93 


28.9 41.8 


30.4 43.3 


25.0 37.9 


-18.3 -5.4 


11.9 24.8 



Table 5.2-6: GPS Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds 



Interference Signal 

at Passive Antenna 

Output (dBm) = 


802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


-108.7 -132.3 


-722.7 -146.3 


-106.2 -129.8 


-98.0 -121.6 


-96.8 -120.4 


GPS 

Interference 

Threshold 

(dBm) 


-17.8 5.8 


-3.8 19.8 


-20.3 3.3 


-28.5 -4.9 


-29.7 -6.1 



Table 5.2-7: MLS Safety Margin (in dB) for Different Combinations of WLAN/Radio Devices, MIPL and 

Interference Thresholds 



Interference Signal 
at Receiver (dBm) = 


802.11b & 


BlueTooth & 


802.11a & 


FRS/GMRS & 


Laptops/PDAs 
& 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


Min 
MIPL 


Ave 
MIPL 


-755.7 


-161.7 


-156.2 


-162.2 


-130.0 


-136.0 


-111.0 


-117.0 


-755.0 


-161.0 


MLS Interference 
Threshold (dBm) 


93.7 99.7 


94.2 100.2 


68.0 74.0 


49.0 55.0 


93.0 99.0 



* For MLS both path loss and receiver susceptibility thresholds came from DO- 199. 

As observed from the tables, interference safety margins can be positive or negative depending upon 
the combination of MIPL and receiver interference thresholds used. WLAN devices generally have better 
safety margin than standard laptops and PDAs based on test data in this effort. 



108 



The exception is 802.1 la devices in MLS band where emissions from most other WLAN devices were 
low and not measurable. Emissions from 802.11a devices became the highest in this band. Due to large 
positive safety margin associated with MLS interference, there appears to be no concern in this band. 
However, the safety margin for MLS seems unusually large. In addition, there was lack of data to 
vaHdate either the interference threshold or the MIPL data provided in RTCA/DO-199 and used in this 
analysis. Additional data in this MLS band would be highly desirable. 

6 Summary and Conclusions 

Emission measurements were conducted on WLAN devices and two-way radios. These observations 
were made: 

a. WLAN device spurious emissions are not any worse (not higher) than spurious 
emissions from computer laptops/PDAs in the aircraft communication and navigation 
bands considered. The exception is in the MLS band with emissions from 802.11a 
devices higher than emissions from the laptops/PDAs. High emissions from 802.11a 
devices in Band 5 is not a concern due to a very large positive safety margin. 

b. The emission levels from WLAN devices and laptops/PDAs are lower than the FCC 
Hmits, but they can be higher than RTCA/DO-160D Category M limits. 

c. Spurious emissions in GS band from FRS and GMRS two-way radios can be 23 dB 
higher than RTCA/DO-160D Category M limit, and 30 dB higher than the maximum 
laptop/PDA emissions in the same band. 

Aircraft IPL measurements were made on four Boeing B747-400 and six Boeing B737-200 aircraft. 
The additional data greatly supplements the low volume of existing IPL data. In addition, the following 
observations were made: 

a. Measurements conducted at window and door locations capture the same minimum 
IPL value as if a full aircraft IPL measurement were conducted. This finding was observed 
for all systems on a B737 aircraft (nose No. 1989) where IPL data were collected at all 
aircraft seats, windows, doors, and locations between seats on one side of the aircraft. 

b. Path loss is greatly affected by the proximity of the aircraft antennas relative to an 
aircraft door. This observation indicates that antenna installation location can affect the 
minimum IPL even for the same aircraft. 

c. The range of lowest and highest minimum IPL can be very large (59 dB for LOC) if all 
past and current data are considered. 

Interference threshold data are inadequate to thoroughly assess the threat from PED-type EMI. Based 
on the limited interference threshold data, safety margin calculations were conducted for many aircraft 
systems. The results show that the safety margins can be negative or positive depending upon the 
interference thresholds (minimum or typical) and the minimum IPL data (the lowest or the average) used. 



109 



7 References 

[I] Ely, J. J.; Nguyen T. X.; Koppen, S. V.; Salud, M. T.; and Beggs J. H.: Wireless Phone Threat Assessment 
and New Wireless Technology Concerns for Aircraft Navigation Radios, Final Report to the FAA, under 
FAA/NASA Interagency Agreement DFTA03-96-X-90001, Revision 9, April 2002. 

[2] RTCA/DO-199, Potential Interference to Aircraft Electronic Equipment from Devices Carried Aboard, 
September 16, 1988. 

[3] RTCA DO-233, Portable Electronic Devices Carried On Board Aircraft, Prepared by SC-177, August 20, 
1996. 

[4] Hill, David A.: Electromagnetic Theory of Reverberation Chambers, Chapter 4, Technical Note 1506, 
National Institute of Standards and Technology, December 1998. 

[5] Veda Inc., CV-580 RE Coupling Validation Experiment Report, Report #79689-96U/P30041, 1 1/15/1996. 

[6] IEEE Computer Society, LAN/MAN Standards Committee, Part 11: Wireless LAN Medium Access Control 
(MAC) and Physical Layer (PHY) Specifications: High-speed Physical Layer in the 5 GHZ Band, September 
16, 1999. 

[7] Bluetooth SIG, Bluetooth Specification Version 1.1, February 22, 2001. 

[8] MIL-STD-462D, Measurement of Electromagnetic Interference Characteristics, January 11, 1993. 

[9] RTCA DO-160D, Change No. 1, Section 20, "Radio Frequency Susceptibility (Radiated and Conducted)", 
Environmental Conditions and Test Procedures for Airborne Equipment, Prepared by SC-135, December 
14, 2000. 

[10] ANSI C63. 4-2000, Interim Standard for Methods of Measurement of Radio-Noise Emissions from Low- 
Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHz, published by the IEEE, 
December 8, 2000. 

[II] Draft ETSI EN 301 908-7 VI. 1.1, Electromagnetic Compatibility and Radio Spectrum Matters; Base Stations 
and User Equipment for IMT-2000 Third Generation Cellular Networks: Part?: Harmonized Standard for 
IMT-2000, CDMA TDD Covering Essential Requirements of Article 3.2 of the R&TTE Directive, April, 2001. 

[12] Koppen, S. V.: A Description of the Software Element of the NASA Portable Electronic Device Radiated 
Emissions Investigation, NASA Contractor Report CR-2002-2 11675, May 2002. 

[13] Crawford, M. L.; and Koepke, G. H.: Design, Evaluation, and Use of a Reverberation Chamber for 
Performing Electromagnetic Susceptibility /Vulnerability Measurements, NBS Technical Note 1092, U. S. 
Department of Commerce/National Bureau of Standards, April 1986. 

[14] Ladbury, J.; Koepke, G.; and Camell, D.: Evaluation of the NASA Langley Research Center Mode-Stirred 
Chamber Facility, NIST Technical Note 1508, January 1998. 



110 



[15] International Electrotechnical Commission (lEC) 61000-4-21, 2003 (Draft) 

[16] 47CFR Ch. 1, Part 15.109, "Radiated Emission Limits", US Code of Federal Regulations, Federal Register 
dated December 19, 2001. 

[17] 47CFR Ch. 1, Part 15.209, "Radiated Emission Limits; General Requirements", US Code of Federal 
Regulations, Federal Register dated December 19, 2001. 

[18] 47CFR Ch. 1, Part 95.635, "Personal Radio Service - Unwanted Radiation", US Code of Federal 
Regulations, Federal Register dated 10-01-98. 

[19] Koepke, G.; Hill, D.; and Ladbury, J.: "Directivity of the Test Device in EMC Measurements", 2000 IEEE 
International Symposium on Electromagnetic Compatibility, Aug. 21-25, 2000. 

[20] World Jet Inventory Report Year-End 2002, Jet Information Service, Inc. 

[21] Ely, Jay J.; Shaver, T.W.; and Fuller, G. L.: Ultrawideband Electromagnetic Interference to Aircraft Radios, 
results of Limited Functional Testing with United Airlines and Eagles Wings Incorporated, in Victorville, 
California, N AS A/TM-2002-2 11949, October 2002. 

[22] Fuller, G.: B737-200 and B747-400 Path Loss Tests, Victorville, California. Eagles Wings Inc., Prepared for 
NASA LaRC under NASA P0# L-16099, Task 1, 2 and 3, 2002. 

[23] Delta AirHnes Engineering, ENGINEERING REPORT Delta/NASA Cooperative Agreement NCC- 1-381 
Deliverable Reports, Report No. 10-76052-20, December 8, 2000. 

[24] International Civil Aviation Organization (ICAO), Aeronautical Telecommunications, Annex 10, Vol. 1 
(Fifth Edition - July 1996). 

[25] International Telecommunication Union (ITU), Recommendations ITU-R M.1477 (2000). 

[26] RTCA/DO-235A, Assessment of Radio Frequency Interference Relevant to the GNSS, Dec. 5, 2002. 

[27] RTCA/DO-229B, Min. Operational Perf Standards for Global Positioning System (GPS)/ Wide Area 
Augmentation System, Oct. 6, 1999. 

[28] RTCA/DO-253A, Min. Operational Perf. Standards for GPS Local Area Augmentation System Airborne 
Equipment, Nov. 28, 2001. 

[29] RTCA/DO-228, Min. Operational Perf. Standards for Global Navitgation Satellite Systems (GNSS) Airborne 
Antenna Equipment, Oct. 10, 1995. 

[30] RTCA/DO-208, Min. Operational Perf. Standards for GPS Airborne Supplemental Navigation Equipment 
using Global Positioning System (GPS), July 12, 199, Change 1, Sept. 21, 1993. 



Ill 



Appendix A: Measurement and Results of Intentional Transmitters Including 
WLAN Devices and Two-Way Radios 

The following charts illustrate WLAN device idle, ping storm envelope, and file transfer (Xfer) 
envelope compared to the baseline (idle and file Xfer) of the host laptop. An equivalent measurement 
noise floor is included in each chart for each band to represent the instrument noise floor, but with 
calibration factors applied as had been done with the emission data. These charts were used to further 
reduce the data to the forms that are found in Sections 3.3 and 3.5 of this report. Table A-1 has details on 
the organization of data charts produced from each wireless communication device tested. Every device 
tested in a wireless technology category was grouped together by measurement bands, so that each device 
may be easily compared with each other. 

The legends in each chart list the data plots by host laptop computer number and WLAN device 
designation. For instance. Figure Al displays emission data plots acquired from Laptop 4 with 802.11a 
WLAN device 11 A-1 installed. Tables 3.2-14 to 3.2-16 list the WLAN device designations and associated 
manufacturers. Table 3.2-4 provides the host laptop designations and manufacturers. 



Table A-1: Organization of Charts in this Section 



Wireless 
Technology 


Bandl 
Figure 


Band 2 
Figure 


Band 3 
Figure 


Band 4 
Figure 


Bands 
Figure 


802.1 lA 


A1-A5 


A6-A10 


A11-A15 


A16-A20 


A21-A25 


802.1 IB 


A26-A32 


A33-A39 


A40-A46 


A47-A53 


A54-A60 


Bluetooth 


A61-A65 


A66-A71 


All-All 


A78-A83 


A84-A89 


FRS 


A90-A93 


A94-A99 


A98-A101 


A102-A105 


A106-A109 


GMRS 


A110-A112 


A113-A115 


A116-A118 


A119-121 


A122-A125 



Al 



A.l 802.11a WLAN Devices 



A.1.1 Band 1 



Band1 Laptop-4 802.11A-1 Idle 
-Band1 Laptop-4 802. 11 A-1 Ping Storm Envelope 
-Bandl Laptop-4 802.11 A-1 File Xfer Envelope 
-Bandl Laptop-4 Baseline 

Bandl Noise Floor 




Ma^^4.,/W^^^ 



^U, ^rfjH^^-^^^^^ 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 



115.5 



118.5 



120 



Figure Al: Laptop 4 and 802.1 lA-1, Band 1. 



-60 



— Bandl Laptop-4 802.1 1A-2 Idle 

Bandl Laptop-4 802.1 1A-2 Ping Storm Envelope 

Bandl Laptop-4 802.1 1A-2 File Xfer Envelope 

Bandl Laptop-4 Baseline 

Bandl Noise Floor 




105 106.5 



111 112.5 114 
Frequency (MHz) 



Figure A2: Laptop 4 and 802.11A-2, Band L 



A2 



Band1 Laptop-4 802.11A-3 Idle 

Band1 Laptop-4 802.11A-3 Ping Storm Envelope 

Band1 Laptop-4 802.11A-3 File Xfer Envelope 

Band1 Laptop-4 Baseline 

Band1 Noise Floor 




111 112.5 114 

Frequency (MHz) 



120 



Figure A3: Laptop 4 and 802.11A-3, Band 1. 



-50 -1 



-100 



-Bandl Laptop-6 802.1 1A-5 Idle 

-Bandl Laptop-6 802.1 1A-5 Ping Storm Envelope 

Bandl Laptop-6 802.1 1A-5 File Xfer Envelope 
-Bandl Laptop-6 Baseline 

Bandl Noise Floor 







'■^w/"" 



I-^/ 



111 112.5 114 

Frequency (MHz) 



Figure A4: Laptop 6 and 802.11A-5, Band L 



A3 



-Band1 Laptop-6 802.11A-6 Idle 

-Band1 Laptop-6 802.11A-6 Ping Storm Envelope 

Band1 Laptop-6 802.11A-6 File Xfer Envelope 
-Band1 Laptop-4 Baseline 

Band1 Noise Floor 




109.5 111 112.5 114 115.J 

Frequency (MHz) 

Figure A5: Laptop 6 and 802.11A-6, Band 1. 



A4 



AJ.2 Band 2 



-60 



-120 



-Band 2 Laptop-4 802.11A-1 Idle 

-Band 2 Laptop-4 802.11A-1 Ping Storm Envelope 

Band 2 Laptop-4 802.11 A-1 File Xfer Envelope 
-Band 2 Laptop-4 Baseline 

Band 2 Noise Floor 




j\ 



^^^^^^^^^.^^M^^^^^^^^^ '^{f^^'^H'i'^^ 



W^ 



325 



326.5 



328 



329.5 331 332.5 334 
Frequency (MHz) 



335.5 



337 



338.5 



340 



Figure A6: Laptop 4 and 802.1 lA-1, Band 2. 



-50 -1 



E 
m 



I -80 



-100 



-Band2 Laptop-4 + 802.1 1A-2 Idle 

-Band2 Laptop-4 + 802.1 1A-2 Ping Storm Envelope 

-Band2 Laptop-4 + 802.1 1A-2 File Xfer Envelope 

-Band2 Laptop-4 Baseline 

-Band2 Noise Floor 




M J:»f 



mm 



rM 



;""-;"^V; i .,.v''.v./*l'A 






331 332.5 334 

Frequency (MHz) 



Figure A7: Laptop 4 and 802.1 lA-2, Band 2. 



A5 



-70 



-Band2 Laptop-4 802.11A-3 Idle 

-Band2 Laptop-4 802.11A-3 Ping Storm Envelope 

-Band2 Laptop-4 802.11A-3 File Xfer Envelope 

-Band2 Laptop-4 Baseline 

- Band2 Noise Floor 




■'^.,^^Y>^Mf^hj'nJw^ 



325 



326.5 



328 



329.5 



331 



335.5 



332.5 334 

Frequency (MHz) 

Figure A8: Laptop 4 and 802.1 lA-3, Band 2. 



337 



338.5 



340 



-60 



Band2 Laptop-6 802.11A-5 Idle 

Band2 Laptop-6 802.11A-5 Ping Storm Envelope 

Band2 Laptop-6 802.11A-5 File Xfer Envelope 

Band2 Laptop-6 Baseline 

Band2 Noise Floor 




'^^^''^^M^^^f^-rf^^MJ^ 



-120 



332.5 334 

Frequency (MHz) 



Figure A9: Laptop 4 and 802.1 lA-5, Band 2. 



A6 



-Band2 Laptop-4 802.11A-6 Idle 
-Band2 Laptop-4 802.11A-6 Ping Storm Envelope 
-Band2 Laptop-4 802.11A-6 File Xfer Envelope 
-Band2 Laptop-4 Baseline 
Band2 Noise Floor 




v.^Hn^%^^ 'Y^ yv^H^'^^v'^'ifyyii^ 



rM ^^^ 



-110 



325 



326.5 



328 



329.5 



331 



332.5 334 
Frequency (MHz) 



335.5 



337 



338.5 



340 



Figure AlO: Laptop 4 and 802.1 lA-6, Band 2. 



A7 



A,1.3 Bands 



I -80 




1110 1140 

Frequency (MHz) 



Figure All: Laptop 6 and 802.1 lA-1, Band 3. 




-100 






-Bands Laptop-6 802.1 1A-2 Idle 

-Bands Laptop-6 802.1 1A-2 Ping Storm Envelope 

Bands Laptop-6 802.1 1A-2 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



960 



990 



1020 



1050 



1170 



1080 1110 1140 

Frequency (MHz) 

Figure A12: Laptop 6 and 802.11A-2, Band 3. 



1200 



1230 



1260 



A8 



-50 7 



I -80 




-110 



Bands Laptop-6 802.1 1A-3 Idle 
-Bands Laptop-6 802.1 1A-3 Ping Storm Envelope 

Bands Laptop-6 802.1 1A-S File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1170 



1050 1080 1110 1140 
Frequency (MHz) 

Figure A13: Laptop 6 and 802.11A-3, Band 3 



1200 



1230 







VVkM^.AM/ \H^W^^..r^^¥^v^v^ ^"^'" 



V ^z 



-120 4 




Bands Laptop-6 +802.1 1A-5 Idle 
-Bands Laptop-6 +802.1 1A-5 Ping Storm Envelope 

Bands Laptop-6 +802.1 1A-5 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1080 1110 1140 

Frequency (MHz) 



1170 



1200 



1230 



Figure A14: Laptop 6 and 802.11A-5, Band 3. 



A9 




^lipvvv^ 






'''\J\:-,.^^s'J^:^- / 



-110 



Bands Laptop-6 + 802.1 1A-6 Idle 
-Bands Laptop-6 + 802.1 1A-6 Ping Storm Envelope 

Bands Laptop-6 + 802.1 1A-6 File Xfer Envelope 
-Bands Laptop-6 Baseline 
- Bands Noise Floor 



1050 1080 1110 1140 1170 

Frequency (MHz) 

Figure A15: Laptop 6 and 802.1 1 A, Band 3. 



AlO 



A.1.4 Band 4 



E 
m 




-100 



-110 



-120 4 



""»■> ^\ 1*. ■ j.'S''»'fc'/''^ ' ' '■'V''' ^ ^''^ " *■ ■ *^ ■' A'!"^* - 



1565 



1567 



1569 



1571 



1573 1575 1577 
Frequency (MHz) 



1579 



1581 



1583 



1585 



Figure A16: Laptop 6 and 802.1 lA-1, Band 4. 



-50 



-60 



E 
m 

■a 



-100 



-110 



-120 



-Band 4 Laptop-6 802.1 1A-2 Idle 
-Band 4 Laptop-6 802.1 1A-2 Ping Storm Envelope 
= Band 4 Laptop-6 802.1 1A-2 File Xfer Envelope 
-Band 4 Laptop-6 Baseline 
Band 4 Noise Floor 




■/' ' ^''''''^'-^i>,rjhr^ 



'■^^i^V^'^'^ 



W^^H^MyV*!^^ 



''T^A^'-^ 



1565 1567 1569 1571 1573 1575 1577 

Frequency (MHz) 



1579 



1581 



1583 



1585 



Figure A17: Laptop 6 and 802.1 lA-2, Band 4. 



All 



I -80 




1573 1575 1577 

Frequency (MHz) 



Figure A18: Laptop 6 and 802.1 lA-3, Band 4. 



Band4 Laptop-6 802.1 1A-5 Idle 
-Band4 Laptop-6 802.1 1A-5 Ping Storm Envelope 
-Band4 Laptop-6 802.1 1A-5 File Xfer Envelope 
-Band4 Laptop-6 Baseline 

Band4 Noise Floor 







1573 1575 1577 

Frequency (MHz) 



Figure A19: Laptop 6 and 802.1 lA-5, Band 4. 



A12 



I -80 



"S -90 



Bancl4 Laptop-6 + 802.11 A-6 Idle 


Band4 Laptop-6 + 802 

Band4 Laptop-6 + 802 


11 A-6 Ping Storm Envelope 
1 1 A-6 File Xfer Envelope 




ne 








1 565 1 567 



1 573 1 575 1 577 
Frequency (MHz) 



1579 1581 1583 1585 



Figure A20: Laptop 6 and 802.1 1 A-6, Band 4. 



A13 



A./.5 Bands 



-50 n 




5060 5068 

Frequency (MHz) 

Figure A21: Laptop 6 and 802.1 lA-1, Band 5. 




5060 5068 

Frequency (MHz) 

Figure A22: Laptop 6 and 802.11A-2, Band 5. 



A14 




-Bands Laptop-6 802.11A-3 Idle 
-Bands Laptop-6 802.11A-3 Ping Storm Envelope 
-Bands Laptop-6 802.11A-3 File Xfer Envelope 
-Bands Laptop-6 Baseline 
Bands Noise Floor 



5020 



5028 



5036 



5044 



5076 



5052 5060 5068 

Frequency (MHz) 

Figure A23: Laptop 6 and 802.11A-3, Band 5. 



5084 



5092 



5100 




-120 



Bands Laptop-6 802.1 1A-S Idle 
-Bands Laptop-6 802.1 1A-S Ping Storm Envelope 

Bands Laptop-6 802.1 1A-S File Xfer Envelope 
-Bands Laptop-6 Baseline 
-Bands Noise Floor 



; 5044 5052 5060 5068 5076 

Frequency (MHz) 

Figure A24: Laptop 6 and 802.11A-5, Band 5. 



A15 



I -80 




5052 5060 5068 

Frequency (MHz) 



Figure A25: Laptop 6 and 802.11A-6, Band 5. 



A16 



A.2 802.11b WLAN Devices 



A.2.1 Band 1 



-50 1 



-60 



— Band1 Laptop-4 + 802. 11 B-2 Idle 

Bandl Laptop-4 + 802.11 B-2 Ping Storm Envelope 

Bandl Laptop-4 + 802.1 1 B-2 File Xfer Envelope 

Bandl Laptop-4 Baseline 

Bandl Noise Floor 




111 112.5 114 

Frequency (MHz) 



Figure A26: Laptop 4 and 802.11B-2, Band 1. 



-50 



I -80 



— Bandl Laptop-4 + 802. 1 1 B-3 Idle 

Bandl Laptop-4 + 802.11 B-3 Ping Storm Envelope 

Bandl Laptop-4 + 802.1 1 B-3 File Xfer Envelope 

Bandl 802.1 IB Baseline 

Bandl Noise Floor 




-110 






'i . .HI ■.%'■/.■'■, ' ; 



^VWaa/^^ 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 



115.5 



117 118.5 



120 



Figure A27: Laptop 4 and 802.11B-3, Band L 



A17 



-50 



-60 



- Band1 Laptop-4 + 802.11 B-5 Idle 

-Bandl Laptop-4 + 802.11 B-5 Ping Storm Envelope 

Bandl Laptop-4 + 802.1 1 B-5 File Xfer Envelope 
-Bandl Laptop-4 Baseline 

Bandl Noise Floor 




-110 



A^'^'^'i^ 






'X/j^'^^jf^ 






105 



106.5 



108 



109.5 



111 112.5 114 

Frequency (MHz) 



115.5 



118.5 



120 



Figure A28: Laptop 4 and 802.11B-5, Band 1. 



-50 



Bandl Laptop-4 + 802.1 1 B-7 Idle 

Bandl Laptop-4 + 802.11 B-7 Ping Storm Envelope 

Bandl Laptop-4 + 802.11 B-7 File Xfer Envelope 

Bandl Laptop-4 Baseline 

Bandl Noise Floor 



-110 



%H^./'^^%M'^i-/'m/^A^ ^"^ 'V^-^H^J 




vV ' ' '/" Va'i'Vv"- • V ■ 



105 



106.5 



108 



109.5 



111 112.5 114 
Frequency (MHz) 



115.5 



118.5 



120 



Figure A29: Laptop 4 and 802.11B-7, Band L 



A18 



-50 7 



Band1 PDA2 + 802.11 B-11 Idle 

Bandl PDA2 + 802.118-11 Ping Storm Envelope 

Bandl PDA2 Baseline 

Bandl Noise Floor 




112.5 114 

Frequency (MHz) 



Figure A30: PDA2 802.1 lB-11, Band 1. 





III 




' ' 


Bandl Laptop-4 + 802.11B-12ldle 




Bandl Laptop-4 + 802.1 1 B-12 File Xfer Envelope 
Bandl Noise Floor 










II 






III 
1 1 1 1 1 1 1 1 
1 1 1 1 1 1 1 1 


|M4V^^ 


v!^S£ii/*i'^3r^'^^^ 


III 
III 
III 
III 
1 1 1 



Frequency (MHz) 

Figure A31: Laptop 4 and 802.11B-12, Band 1. 



A19 



-50 



-70 




-Band1 Laptop-4 + 802.11B-13 Idle 
-Band1 Laptop-4 + 802.118-13 Ping Storm Envelope 
-Bandl Laptop-4 + 802.1 1B-1 3 File Xfer Envelope 
-Bandl Laptop-4 Baseline 
Bandl 802.1 IB Noise Floor 



-100 



■*' , J . .': (sIA .'■•.'■■., '■''•As 



-120 4 



pI i j«J 



I.JIL: i : .M 







111 112.5 114 

Frequency (MHz) 



Figure A32: Laptop 4 and 802.11B-13, Band 1. 



A20 



A.2.2 Band 2 




I -80 



-100 



Band2 Laptop-4 + 802.11 B-2 Idle 
-Band2 Laptop-4 + 802.11 B-2 Ping Storm Envelope 
- Band2 Laptop-4 + 802.1 1 B-2 File Xfer Envelope 
-Band2 Laptop-4 Baseline 

Band2 Noise Floor 




'WV^V^JV 



l-VVw; 









325 326.5 328 329.5 331 332.5 334 

Frequency (MHz) 



335.5 



337 



338.5 



340 



Figure A33: Laptop 4 and 802.11B-2, Band 2. 



-70 



I -80 



-110 




- Band2 Laptop-4 + 802.1 1 B-3 Idle 

-Band2 Laptop-4 + 802.1 1 B-3 Ping Storm Envelope 

Band2 Laptop-4 + 802.1 1 B-3 File Xfer Envelope 
-Band2 Laptop-4 Baseline 

Band2 Noise Floor 




M/^^^^'-fH, N\k^r. /A;^/v^W% ji J^^ '' ^ '%yv^4^,;V^/^^/fHf^ 






329.5 331 332.5 334 335.5 
Frequency (MHz) 

Figure A34: Laptop 4 and 802.1 lB-3, Band 2. 



A21 



-60 



— Band2 Laptop-4 + 802.11B-5 Idle 

— Band2 Laptop-4 + 802.11B-5 Ping Storm Envelope 

— Band2 Laptop-4 + 802.11B-5 File Xfer Envelope 

— Band2 Laptop-4 Baseline 
- -Band2 Noise Floor 








Hh 



4. 



'^"^^"^^^ 






325 326.5 328 329.5 331 332.5 334 335.5 

Frequency (MHz) 

Figure A35: Laptop 4 and 802.1 lB-5, Band 2. 



337 



338.5 



340 



-60 



- Band2 Laptop-4 + 802. 11 B-7 Idle 
-Band2 Laptop-4 + 802.11 B-7 Ping Storm Envelope 
-Band2 Laptop-4 + 802.11 B-7 File Xfer Envelope 
-Band2 Laptop-4 Baseline 
Band2 Noise Floor 











325 



326.5 



328 



329.5 



335.5 



331 332.5 334 

Frequency (MHz) 

Figure A36: Laptop 4 and 802.11B-7, Band 2. 



337 



338.5 



340 



A22 



-50 



-60 



-110 



-120 



Band2 PDA2 + 802.1 1 B-1 1 Idle 

Band2 PDA2 + 802.118-11 Ping Storm Envelope 

Band2 PDA2 Baseline 

Band2 Noise Floor 







325 



326.5 



328 



335.5 



329.5 331 332.5 334 

Frequency (MHz) 

Figure A37: PDA2 and 802.1 lB-11, Band 2 



337 



338.5 



340 



-50 T- 



I -80 



' Band2 Laptop-4 + 802. 1 1 B-1 2 Idle 

-Band2 Laptop-4 + 802.11 B-1 2 Ping Storm Envelope 

Band2 Laptop-4 + 802.1 1B-12 File Xfer Envelope 
-Band2 Laptop-4 Baseline 

Band2 Noise Floor 




326.5 



329.5 



331 332.5 334 
Frequency (MHz) 



337 



340 



Figure A38: Laptop 4 and 802.1 lB-12, Band 2. 



A23 



-50 



Band2 Laptop-4 + 802.11B-13 Idle 

Band2 Laptop-4 + 802.118-13 Ping Storm Envelope 

Band2 Laptop-4 + 802.1 1B-1 3 File Xfer Envelope 

Band2 Laptop-4 Baseline 

Band2 Noise Floor 




W^^V^M/^^^^ ' "^ '""W^^H^M/^V^ - - - v^ 



-120 4- 



331 332.5 334 

Frequency (MHz) 



Figure A39: Laptop 4 and 802.1 lB-13, Band 2. 



A24 



A.2.3 Band 3 




-100 



-120 



»-\:!\.rV;, .A. A 



Hi^r-^V^r \.!'\.f\}^-\:'^i'^'^'\r ^V'v/V 



- Bands Laptop-6 + 802.1 1 B-2 Idle 

-Bands Laptop-6 + 802.11 B-2 Ping Storm Envelope 

- Bands Laptop-6 + 802.1 1 B-2 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1110 
Frequency (MHz) 



Figure A40: Laptop 6 and 802.11B-2, Band 3. 




-110 



- Bands Laptop-6 + 802.1 1 B-S Idle 

-Bands Laptop-6 + 802.11 B-S Ping Storm Envelope 

- Bands Laptop-6 + 802.1 1 B-S File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



960 



990 



1020 



1050 



1080 1110 1140 

Frequency (MHz) 



1170 



1200 



1230 



1260 



Figure A41: Laptop 6 and 802.1 lB-3, Band 3. 



A25 




-90 






^, A^ 



Wl/ ' '^'' ^M..vV^V^ y^-NvvW 






-100 



-120 



= Bands Laptop-6 + 802.1 1 B-5 Idle 

-Bands Laptop-6 + 802.11 B-5 Ping Storm Envelope 

- Bands Laptop-6 + 802.1 1 B-5 File Xfer Envelope 

-Bands Laptop-6 Baseline 

-Bands Noise Floor 



1110 
Frequency (MHz) 



1140 



1170 



Figure A42: Laptop 6 and 802.1 lB-5, Band 3. 



1200 



1230 




"^i/;- 'V^''^' '.''''''• ,f\r-^^ \t'^j^^'\r '^'^ "^Vv 



-100 



-120 



Bands Laptop-6 + 802.1 1B-7 Idle 
-Bands Laptop-6 + 802.1 1B-7 Ping Storm Envelope 

Bands Laptop-6 + 802.1 1 B-7 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1080 1110 1140 

Frequency (MHz) 



1170 



Figure A43: Laptop 6 and 802.11B-7, Band 3. 



1200 



1230 



A26 



-60 



- Bands PDA2 + 802.1 1 B-1 1 Idle 

- Bands PDA2 + 802.1 1 B-1 1 Ping Storm Envelope 
-Bands PDA2 Baseline 

-Bands Noise Floor 




Figure A44: PDA2 and 802.1 lB-11, Band 3. 




,^/v^^^V^^v'\^^V;«"■/^W'^^^'V '^"^y% 




Bands Laptop-6 + 802.1 1 B-1 2 Idle 
-Bands Laptop-6 + 802.11 B-1 2 Ping Storm Envelope 
■ Bands Laptop-6 + 802.1 1 B-1 2 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1110 
Frequency (MHz) 



1140 1170 1200 1230 1260 



Figure A45: Laptop 6 and 802.1 lB-12, Band 3. 



A27 




-100 



Bands Laptop-6 + 802.11 B-1 3 Idle 
-Bands Laptop-6 + 802.11 B-1 3 Ping Storm Envelope 
-Bands Laptop-6 + 802.11 B-1 3 File Xfer Envelope 
-Band3 Laptop-6 Baseline 
- Band3 Noise Floor 



-120 4- 



1080 1110 1140 
Frequency (MHz) 



1170 



1200 



Figure A46: Laptop 6 and 802.1 lB-13, Band 3. 



A28 



A.2.4 Band 4 



I -80 



-Band4 Laptop-6 + 802.11 B-2 Idle 

-Band4 Laptop-6 + 802.11 B-2 Ping Storm Envelope 

Band4 Laptop-6 + 802.1 1 B-2 File Xfer Envelope 
-Band4 Laptop-6 Baseline 
- Band4 Noise Floor 



-110 








1565 



1567 



1569 



1571 



1573 1575 1577 

Frequency (MHz) 



1579 



1581 



1583 



1585 



Figure A47: Laptop 6 and 802.1 lB-2, Band 4. 



-50 1 



-60 



-70 



I -80 



- Band4 Laptop-6 + 802.1 1 B-3 Idle 

-Band4 Laptop-6 + 802.11 B-3 Ping Storm Envelope 

- Band4 Laptop-6 + 802.1 1 B-3 File Xfer Envelope 
-Band4 Laptop-6 Baseline 

Band6 Noise Floor 



-110 



/v/W^"^Aa/^ 










1573 1575 1577 

Frequency (MHz) 



Figure A48: Laptop 6 and 802.1 lB-3, Band 4. 



A29 



-50 1 



-60 



-Band4 Laptop-6 + 802.11B-5 Idle 
-Band4 Laptop-6 + 802.11B-5 Ping Storm Envelope 
= Band4 Laptop-6 + 802.11B-5 File Xfer Envelope 
-Band4 Laptop-6 Baseline 
Band4 Noise Floor 




1 573 1 575 1 577 

Frequency (MHz) 



Figure A49: Laptop 6 and 802.11B-5, Band 4. 



-50 



-70 



I -80 



Band4 Laptop-6 + 802.11 B-7 Idle 
-Band4 Laptop-6 + 802.11 B-7 Ping Storm Envelope 
= Band4 Laptop-6 + 802.1 1 B-7 File Xfer Envelope 
-Band4 Laptop-6 Baseline 

Band4 Noise Floor 




WvO^^^iy 



-110 



1^4^^ 



1 573 1 575 1 577 

Frequency (MHz) 



Figure A50: Laptop 6 and 802.1 lB-7, Band 4. 



A30 




-120 ^ 



1565 1567 1569 1571 1573 1575 1577 1579 1581 

Frequency (MHz) 

Figure A51: PDA2 and 802.1 lB-11, Band 4. 



1583 1585 



-50 T- 



Band4 Laptop-6 + 802.1 1 B-12 Idle 

Band4 Laptop-6 + 802.118-12 Ping Storm Envelope 

Band4 Laptop-6 + 802.11 B-12 File Xfer Envelope 

Band4 Laptop-6 Baseline 

Band4 Noise Floor 




9 1571 1573 1575 1577 1579 

Frequency (MHz) 

Figure A52: Laptop 6 and 802.1 lB-12, Band 4. 



1583 1585 



A31 



-60 



I -80 



-100 



-120 4 







III 

III 






Band4 Laptop-6 + 802.1 1 B-1 3 Idle 

Band4 Laptop-6 + 802.118-13 File Xfer Envelope 
Band4 Laptop-6 + 802.11 B-1 3 Ping Storm Envelope 

Band4 Noise Floor 




! ! 










1 


III 
III 
III 






a 1 11 1 


kl 


upfpjw^ 




fifk 


1 ' 1 1 


III 

III 

1 1 1 1 1 1 1 

1 1 1 1 
III 
. — — — 1 — ■ 1 — \ — \ \ — ——^— 



1573 1575 1577 

Frequency (MHz) 



Figure A53: Laptop 6 and 802.1 lB-13, Band 4. 



A32 



A.2.5 Band 5 



-120 
5020 





III 






Bands Laptop-6 + 802. 11 B-2 Idle 

Bands Laptop-6 + 802.11 B-2 Ping Storm Envelope 

Bands Laptop-6 + 802.1 1 B-2 File Xfer Envelope 

Bands Lanton-fi Ra.qeline 




I I 




1 






Joise Floor 






«^. i J^/h 1 Jl 


1 . ^i^ m 








^J,^^^^^^ 


f'**^!^ 


«»'W%*^1J****^W^^^ 












: : 










I I 











1 5044 5052 5060 5068 5076 
Frequency (MHz) 

Figure A54: Laptop 6 and 802.11B-2, Band 5. 



-60 



-110 



-120 
5020 





II 




I I I 


— Bands Laptop-6 802. 1 1 B-3 Idle 

Bands Laptop-6 802.11 B-3 Ping Storm 

Envelope 

Bands Laptop-6 802.1 1 B-3 File Xfer Envelope 

Band Noise Floor 




! ! ! 






^^.^^^^^^^ 


I I I I 


1 1 1 





5028 



5036 



5044 



5052 5060 5068 
Frequency (MHz) 



5076 



5084 



5092 



5100 



Figure A55: Laptop 6 and 802.1 lB-3, Band 5. 



A33 







III 








Bands Laptop-6 + 802. 11 B-5 Idle 

Bands Laptop-6 + 802.11 B-5 Ping Storm Envelope 

Bands Laptop-6 + 802.1 1 B-5 File Xfer Envelope 

Bands Noise Floor 




7n 


! ! 












I ! 


I li . . . 1 1 1 i 






5,^,^^^ 








! 


i?n 


1 1 1 



5060 5068 

Frequency (MHz) 



Figure A56: Laptop 6 and 802.1 lB-5, Band 5. 



-50 n 



-120 
5020 



III 


Bands Laptop-6 802. 1 1 B-7 Idle 






E 


3andS Laptop-6 802.1 1 B-7 File Xfer Envelope 
3andS Laptop-6 Baseline 
3andS Noise Floor 


III 




E 










K 


l^,,,^//^^**^^ 


WNMV^^ 


f^(*«-V 


^•0^ 


uU^^ 


III 










III 





















5060 5068 

Frequency (MHz) 



Figure A57: Laptop 6 and 802.1 lB-7, Band 5. 



A34 



-100 



-120 





II 






Bands PDA2 + 802.1 1 B-1 1 Idle 

Bands PDA2 + 802.1 1 B-1 1 Ping Storm Envelope 

Bands Noise Floor 




! ! ! 






















1 




II 
II 












1 










: : : 











5052 5060 5068 

Frequency (MHz) 



Figure A58: PDA2 and 802.1 lB-11, Band 5. 



-50 



-60 



-70 



-80 



-90 



-100 



-110 



-120 
5020 





II 






Bands Laptop-6 802. 1 1 B-1 2 Idle 

Bands Laptop-6 802.11 B-1 2 Ping Storm Envelope 

Bands Laptop-6 802.11 B-1 2 File Xfer Envelope 

Bands Noise Floor 




II 








III 
III 


II 
III 
III 

II 




gg^^<«M/)N^^%*^^ 




1 1 1 1 1 1 1 


1 1 1 1 1 1 1 



5028 



5036 



5076 



5044 5052 5060 5068 
Frequency (MHz) 

Figure A59: Laptop 6 and 802.1 lB-12, Band 5. 



5084 



5092 



5100 



A35 



-50 T- 



-70 



- Bands Laptop-6 + 802. 11 B-1 3 Idle 

-Bands Laptop-6 + 802.11 B-1 3 Ping Storm Envelope 

Bands Laptop-6 + 802.11 B-1 3 File Xfer Envelope 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



-90 



5052 5060 5068 

Frequency (MHz) 



Figure A60: Laptop 6 and 802.1 lB-13, Band 5. 



A36 



A.3 Bluetooth Devices 



A.3.1 Bandl 



-50 




-Bandl Laptop-4 BLUE-2 Idle 
-Bandl Laptop-4 BLUE-2 Page 
-Bandl Laptop-4 Baseline 
Bandl Noise Floor 



-110 



-120 



105 106.5 108 109.5 111 112.5 114 115.5 

Frequency (MHz) 

Figure A61: Laptop 4 and BLUE-2, Band L 



117 



118.5 



120 



-50 




% -80 



-100 



-110 



^^^^^.^^.^^^ K. 



-120 



Bandl Laptop-4 BLUE-6 Idle 
-Bandl Laptop-4 BLUE-6 Page 
-Bandl Laptop-4 Baseline 

Bandl Noise Floor 



%J^'^--^\jf'' '^hS^^' 



105 



106.5 



108 



115.5 



109.5 111 112.5 114 

Frequency (MHz) 

Figure A62: Laptop 4 and BLUE-6, Band L 



117 



118.5 



120 



A37 



I -80 



-Band1 Laptop-4 BLUE-8 Idle 
-Band1 Laptop-4 BLUE-8 Page 
-Band1 Laptop-4 Baseline 
Band1 Noise Floor 




-110 



109.5 



115.5 



112.5 114 
Frequency (MHz) 

Figure A63: Laptop 4 and BLUE-8, Band L 




-Bandl PRN1 BLUE-10 Idle 
-Bandl PRN1 BLUE-10 Page 
-Bandl PRN Baseline 
-Bandl Noise Floor 



-120 



109.5 111 112.5 114 115.; 
Frequency (MHz) 

Figure A64: PRNl and BLUE-10, Band 1. 



A38 



I -80 



-Band1 Laptop-4 BLUE-11 Idle 
-Band1 Laptop-4 BLUE-11 Page 
-Bandl Laptop-4 Baseline 
Bandl Noise Floor 




-110 



I -80 



^ -90 



109.5 111 112.5 114 115.5 
Frequency (MHz) 

Figure A65: Laptop 4 and BLUE-11, Band 1. 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 



118.5 





III 




! ! 






Bandl PDA-1 BLUE-12 Page 

Bandl Noise Floor 












' ' ' 


' 


^^U***Nv«\,^,,j^j^,^^^^^^ 





120 



Figure A66: PDAl and BLUE-12, Band 1. 



A39 



A.3.2 Band 2 



-60 



Band2 Laptop-4 BLUE-2 Idle 
-Band2 Laptop-4 BLUE-2 Page 
-Band2 Laptop4 Baseline 
-Band2 Noise Floor 




'^rf^^^^i A^jl^^^/^^//W% -^i^ '■■ ''X^/J'J''j^^y0>\;^vf]^^ 



332.5 334 

Frequency (MHz) 



Figure A67: Laptop 4 and BLUE-2, Band 2. 



I -80 




-110 



329.5 



331 



335.5 



332.5 334 
Frequency (MHz) 

Figure A68: Laptop 4 and BLUE-6, Band 2. 



A40 



Band2 Laptop-4 BLUE-8 Idle 
-Band2 Laptop-4 BLUE-8 Page 
-Band2 Laptop-4 Baseline 

Band2 Noise Floor 



I -80 




A^^/v^v^ ^^J^^^i^^/JKJ\ ' ^ ""-^aJ-J^^^,;^^!^^ 



-110 



329.5 331 332.5 334 335.5 
Frequency (MHz) 

Figure A69: Laptop 4 and BLUE-8, Band 2. 



-Band2PRNBLUE-1 Oldie 
-Band2 PRN BLUE-10 Page 
-Band2 PRN Baseline 
- Band2 Noise Floor 



I -80 




-120 



329.5 331 332.5 334 335.; 
Frequency (MHz) 

Figure A70: PRNl and BLUE-10, Band 2. 



A41 



I -80 



-110 



Band2 Laptop-4 BLUE-11 


Idle 


Band2 Laptop-4 BLUE-11 


Page 


Band2 Noise Floor 






^€^^SJ■■'^l^mJU^''^-^^ 






329.5 



331 



335.5 



332.5 334 
Frequency (MHz) 

Figure A71: Laptop 4 and BLUE-1 1, Band 2. 



-Band2PDA-1 BLUE-1 2 Idle 
-Band2 PDA-1 BLUE-1 2 Page 
-Band2 PDA-1 Baseline 
Band2 Noise Floor 



325 326.5 328 329.5 331 332.5 334 335.5 

Frequency (MHz) 

Figure A72: PDAl and BLUE-12, Band 2. 



337 




338.5 



340 



A42 



A.3.3 Band 3 



-50 -1 



% -80 



^ -90 
cc 




-100 






Vi^;^yv/^ "^^-^l^x^r' 



Bands Laptop-6 BLUE-2 Idle 
-Bands Laptop-6 BLUE-2 Page 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



960 990 1020 1050 



1080 1110 1140 

Frequency (MHz) 

Figure A73: Laptop 6 and BLUE-2, Band 3 



1170 1200 1230 1260 



-50 -1 




% -80 



^ -90 Nr^tr-T/VtrV^ 



-■ \rJ^^^V^f[: ' \ ^f\,f^\f^'^^J^^^\^ 



hr^"\^. A'^'H rv^'^ '^ yk/vV Wyl^^yM^Af^ 




-Bands Laptop-6 BLUE-6 Idle 
-Bands Laptop-6 BLUE-6 Page 
-Bands Laptop-6 Baseline 
-Bands Noise Floor 



960 990 1020 1050 



1080 1110 1140 

Frequency (MHz) 



1170 1200 1230 1260 



Figure A74: Laptop 6 and BLUE-6, Band 3. 



A43 




- ^■. .jA'^.A . A ^ khi. ^U:>. /^.AA,..oAv^fUi.AMAj.iy^..My^-^'^^^ 






-110 



Bands Laptop-6 BLUE-8 Idle 
-Bands Laptop-6 BLUE-8 Page 
-Bands Laptop-6 Baseline 

Bands Noise Floor 



1050 



1170 



1080 1110 1140 
Frequency (MHz) 

Figure A75: Laptop 6 and BLUE-8, Band 3. 



-60 



Bands PRNBLUE-10 Idle 
Bands PRNBLUE-10 Page 
Bands PRN Baseline 
Bands Noise Floor 




"^ „yv^v^ 



^.«V^/'^,;^^\;^■'V 'VV^Vv 



W^ 



fS^^^^ 






>n4W 



-100 



-110 



-120 - 



960 



990 



1020 



1050 



1080 1110 1140 

Frequency (MHz) 



1170 



Figure A76: PRN and BLUE- 10, Band 3. 



1200 



1230 



1260 



A44 



Bands Laptop-6 BLUE-11 Idle 
Bands Laptop-6 BLUE-11 Page 
Bands Laptop-6 Baseline 
Bands Noise Floor 




-110 



1050 



1170 



1080 1110 1140 
Frequency (MHz) 

Figure A77: Laptop 6 and BLUE-1 1, Band 3. 




I -80 



-110 



-Bands PDA-1 BLUE-12 Idle 
-Bands PDA-1 BLUE-12 Page 
-Bands PDA-1 Baseline 
- Bands Noise Floor 



1020 1050 



1080 1110 1140 1170 1200 
Frequency (MHz) 



1230 1260 



Figure A78: PDAl and BLUE-12, Band 3. 



A45 



A.3.4 Band 4 



Band4 Laptop-6 BLUE-2 Idle 

Band4 Laptop-6 BLUE-2 Page 

Band4 Laptop-6 Baseline 

Band4 Noise Floor 




-110 



-120 
1565 



1573 1575 1577 
Frequency (MHz) 



Figure A79: Laptop 6 and BLUE-2, Band 4. 



-Band4 Laptop-6 BLUE-6 Idle 
-Band4 Laptop-6 BLUE-6 Page 
-Band4 Laptop-6 Baseline 
Band4 Noise Floor 







1573 1575 1577 

Frequency (MHz) 



1583 1585 



Figure A80: Laptop 6 and BLUE-6, Band 4. 



A46 











1 






, 


Band4 Laptop-6 BLUE-8 Idle 








Band4 Laptop-6 BLUE-8 Page 






















Band4 Noise Floor 








1 








E 
m 
















Q. 


! ! ! 1 




« 




' ' ' II 




(0 




1 






"O .qn 




J 






(0 -yu 






\ 1 . ii 


^1 


(0 




illl liiAl^i 1 ^ t 


, '1.1 iLUL iL 


iA. 


£ 




iUuryi..iLML.iiAi . . . .k. 1, 


M J.I. ^JULlilJi..kiiWMXr'^ 


-100 




Jnii^ 


tilfflu 1- i.tf(|AlillUF^^ ^J^WnTfT'' ^- 










fS^'^'i^'^'^H-^ 








I I I 1 I 


-120 





1571 



1579 



1573 1575 1577 
Frequency (MHz) 

Figure A81: Laptop 6 and BLUE-8, Band 4. 



-50 




I -80 



-100 



-110 



-120 4 



Band4PRNBLUE-1 Oldie 
Band4PRNBLUE-10Page 
Band4 PRN Baseline 
Band4 Noise Floor 



1565 



1567 



1569 



1571 



1573 1575 1577 

Frequency (MHz) 

Figure A82: PRN andBLUE-10, Band4. 



1579 



1581 



1583 



1585 



A47 



-70 



-Band4 Laptop-6 BLUE-11 Idle 
-Band4 Laptop-6 BLUE-11 Page 
-Band4 Laptop-6 Baseline 
Band4 Noise Floor 




-120 
1565 



^!31-W^M 




1571 1573 1575 1577 1579 
Frequency (MHz) 

Figure A83: Laptop 6 and BLUE-1 1, Band 4. 




1573 1575 1577 

Frequency (MHz) 

Figure A84: PDAl and BLUE-12, Band 4. 



A48 



A.3.5 Band 5 



-60 



-Bands Laptop-6 BLUE-2 Idle 
-Bands Laptop-6 BLUE-2 Page 
-Bands Laptop-6 Baseline 
-Bands Noise Floor 



gjj^^^^^'/'V*'^^^^ 



-110 



5044 



5052 



5076 



5060 5068 

Frequency (MHz) 

Figure A85: Laptop 6 and BLUE-2, Band 5. 




Frequency (MHz) 

Figure A86: Laptop 6 and BLUE-6, Band 5. 



A49 



-70 



-Bands Laptop-6 BLUE-8 Idle 
-Bands Laptop-6 BLUE-8 Page 
-Bands Laptop-6 Baseline 
Bands Noise Floor 




W4«r^^V^J^^t* 



-110 



-120 
5020 



5044 



5076 



5052 5060 5068 

Frequency (MHz) 

Figure A87: Laptop 6 and BLUE-8, Band 5. 



-60 



-110 



-120 
5020 





1 






Bands PRN BLUE-10 Idle 

Bands PRN BLUE-10 Page 

Bands PRN Baseline 

Bands Noise Floor 




I ! ! I 






1 




1 

1 

1 1 

1 1 1 1 1 1 1 

.1 1 . 1. 


w^vn«^H*»/^^^y,^ 


1 1 1 1 1 1 1 1 


' ' ' ' ' 


' ' ' ' ' 



5044 5052 5060 5068 50i 
Frequency (MHz) 

Figure A88: PRN and BLUE-10, Band 5. 



A50 



-70 



-Bands Laptop-6BLUE-11 Idle 
-Bands Laptop-6 BLUE-11 Page 
-Bands Laptop-6 Baseline 
Bands Noise Floor 



-110 



-120 
5020 



5044 



5052 



5076 



5060 5068 

Frequency (MHz) 

Figure A89: Laptop 6 and BLUE-1 1, Band 5. 



- Bands PDA-1 BLUE-1 2 Idle 
-Bands PDA-1 BLUE-1 2 Page 
-Bands PDA-1 Baseline 
-Bands Noise Floor 



-120 ^ — 
5020 



5060 
Frequency (MHz) 



Figure A90: PDAl and BLUE-12, Band 5. 



A51 



A.4 FRS Radios 



A.4.1 Band 1 



Band1 FRS1&2 Idle 

-Band1 FRS1&2 Voice 

Band1 Noise Floor 



^^^.^V,.^^^^^,,.y,v^#y?w^^ 



v7u^ 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 

Figure A91: FRS 1&2, Band 1. 



115.5 



118.5 



120 



Bandl FRS3&4 Idle 

-Bandl FRS3&4 Voice 

Bandl Noise Floor 




-120 



y^/\iu/t>4v 



\/^K 



^ 'Sf 



)9.5 111 112.5 114 

Frequency (MHz) 

Figure A92: FRS 3&4, Band 1. 



A52 



-50 



-60 



-70 



-80 



-90 



-100 



-110 



Bandl FRS5&6 Idle 

-Bandl FRS5&6 Voice 

Bandl Noise Floor 




-120 



105 106.5 108 109.5 111 112.5 114 115.5 117 

Frequency (MHz) 



118.5 120 



Figure A93: FRS 5&6, Band 1. 



-50 



-60 



-70 



-80 



-90 



-100 



-110 



-120 



1 1 1 1 


1 
1 




1 1 1 1 


Bandl FRS7&8 Idle 

Bandl FRS7&8 Voice 

Bandl Noise Floor 








1 1 1 1 




















1 1 1 1 








! ! ! ! 








V^..^^^M.^yM/ 


A4^ 




> 


/W^ 


r -^ 


^^■ 













105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 

Figure A94: FRS 7&8, Band 1. 



115.5 



117 



118.5 



120 



A53 



A.4.2 Band 2 



-120 4 
325 



1 1 1 1 


1 







Band2 FRS1&2 Idle 

Band2FRS1&2 Voice 

Band2 Noise Floor 










I 




, 




1 . AA.i kv 11 ih . Am .», A,. 1 ,^1 iiijlP 


1 ik. . 


,,^/A/»^M^i«^^ 


W^fi)^ 


1 1 1 1 1 



-100 



-110 



332.5 334 

Frequency (MHz) 



Figure A95: FRS 1&2, Band 2. 



Band2 FRS3&4 Idle 
-Band2 FRS3&4 Voice 
-Band2 Noise Floor 



kjJi^^^ 



i^^tj 




19.5 331 332.5 334 

Frequency (MHz) 

Figure A96: FRS 3&4, Band 2. 



A54 



-40 



-50 



-60 



-70 



-80 



-90 



-Band2FRS5&6ldle 
-Band2 FRS5&6 Voice 
-Band2 Noise Floor 





-110 



W^ ^'yr'Y^V'''\4^ ^/^ 



-100 



-110 



29.5 331 332.5 334 

Frequency (MHz) 

Figure A97: FRS 5&6, Band 2. 




\^f/^%A>^^'U^wl [j 



331 332.5 334 33 

Frequency (MHz) 

Figure A98: FRS 7&8, Band 2. 



A55 



A.4.3 Band 3 



-40 



I -70 



-Bands FRS1&2 Idle 
-Bands FRS1&2 Voice 
-Bands Noise Floor 



ill, i i , r' I I : ' , 



960 990 1020 1050 



1080 1110 1140 
Frequency (MHz) 

Figure A99: FRS 1&2, Band 3. 



1170 1200 1230 1260 




960 990 1020 1050 1080 



1110 1140 
Frequency (MHz) 



1170 1200 1230 1260 



Figure AlOO: FRS 3&4, Band 3. 



A56 



I -80 




-110 



1050 



1080 1110 1140 
Frequency (MHz) 

Figure AlOl: FRS 5&6, Band 3. 



-50 



— Bands FRS 7&8 Idle 

Bands FRS 7&8 Voice 

Bands Noise Floor 



V^f' 



V 



-100 



-^Wvyv^K^^I 



kv:^Jv„|^jS^„ ^^j 



VW'HW'^^^^^V^ 




1080 1110 1140 ir 

Frequency (MHz) 

Figure A102: FRS 7&8, Band 3. 



A57 



A.4.4 Band 4 




Band4FRS1&2 Idle 
Band4FRS1&2 Voice 
Band4 Noise Floor 



,^^,,^^¥^^4^ 



1571 



1573 1575 1577 

Frequency (MHz) 

Figure A103: FRS 1&2, Band 4. 



-50 1 



I -80 



^ -90 



-100 



-Band4FRS3&4ldle 

-Band4FRS3&4 Voice 

Band4 Noise Floor 




4, 



'/y>^ 



U'^^ 



\ka.^^\ Aj Uv^y, uAV^y^^/^- Uax4J [y 



,^H,WMa./^/^^^, 



1565 1567 1569 1571 1573 1575 1577 

Frequency (MHz) 

Figure A104: FRS 3&4, Band 4. 



1579 



1581 



1583 



1585 



A58 



-70 



-Band4FRS5&6ldle 
-Band4 FRS5&6 Voice 
- Band4 Noise Floor 




^)'^\rh\^-^ 



-110 



^jy^-ln/w^"- 



'i^VAW-v^J K.\^^^]^J^^' 



f^if' 



-^^ 



St^^^vvvjS^ 



1571 



1573 1575 1577 

Frequency (MHz) 

Figure A105: FRS 5&6, Band 4. 



-60 



Band4 FRS7&8 Idle 

-Band4FRS7&8 Voice 

Band4 Noise Floor 




^4^M^4lV^jU' 




y 



-110 



vWv\/v^v^ 



m 



1571 



1573 1575 1577 

Frequency (MHz) 

Figure A106: FRS 7&8, Band 4. 



A59 



A.4.5 Band 5 



-40 



Bands FRS1&2 Idle 

-Bands FRS1&2 Voice 

Bands Noise Floor 



I -60 



Iv^l^^^^^^ 



-90 



JLJU'« 



A^h^ 



?P^U^.^^ 



5044 



5052 5060 5068 

Frequency (MHz) 

Figure A107: FRS 1&2, Band 5. 



-40 -1 




I -70 



^ -80 
tr 



-90 



yk^^Kj^^ 



U k^A 



Bands FRS3&4 Idle 

-Bands FRS3&4 Voice 

Bands Noise Floor 



5020 



5028 



5036 



5044 



5052 5060 5068 

Frequency (MHz) 

Figure A108: FRS 3&4, Band 5. 



5076 



5084 



5092 



5100 



A60 



-50 



- Bands FRS5&6 Idle 

-Bands FRSS&6 Voice 

Bands Noise Floor 



|»4l%AA^^ 




-90 



j'V'^^.^^' 




5044 



5052 



5060 5068 
Frequency (MHz) 

Figure A109: FRS 5&6, Band 5. 



-50 



-Bands FRS7&8 Idle 

- Bands FRS7&8 Voice 

Bands Noise Floor 



j^Ju^u^vVv*^^"^^ 



-100 



5036 5044 5052 5060 5068 5076 
Frequency (MHz) 

Figure AllO: FRS 7&8, Band 5. 



5084 5092 5100 



A61 



A.5 GMRS Radios 



A.5.1 Bandl 



-50 1 



I -80 



^ -90 



-100 



-Bandl GMRS 1&2 Idle 
-Bandl GMRS 1&2 Voice 
Bandl Noise Floor 




iM|/vVH,U^^^ 




105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 



115.5 



Figure Alll: GMRS 1&2, Band 1. 



118.5 



120 



-50 1 




-100 



111 112.5 114 
Frequency (MHz) 

Figure A112: GMRS 3&4, Band 1. 



A62 



-110 



Bandl GMRS 5&6 Idle 
Bandl GMRS 5&6 Voice 
Bandl Noise Floor 




109.5 111 112.5 114 

Frequency (MHz) 

Figure A113: GMRS 5&6, Band 1. 



A63 



A.5.2 Band 2 




-40 



-50 



S, -60 



Band2GMRS 1&2 Idle 
-Band2GMRS 1&2 Voice 
Band2 Noise Floor 



325 



329.5 331 332.5 

Frequency (MHz) 

Figure A114: GMRS 1&2, Band 2. 



335.5 



338.5 



340 



-30 -1 




325 326.5 



332.5 334 
Frequency (MHz) 

Figure A115: GMRS 3&4, Band 2. 



335.5 



338.5 



340 



A64 



Band2 GMRS 5&6 Idle 
-Band2GMRS5&6 Voice 
Band2 Noise Floor 




329.5 331 332.5 334 

Frequency (MHz) 

Figure A116: GMRS 5&6, Band 2. 



A65 



A.5.3 Band 3 



-60 



-110 



]|f%¥V'Vw^^^^^^ 



XiSittMk 



Bands GMRS 1&2 Idle 
-Bands GMRS 1&2 Voice 
Bands Noise Floor 



1050 1080 1110 1140 

Frequency (MHz) 

Figure A117: GMRS 1&2, Band 3. 



-40 



Bands GMRS S&4 Idle 
Bands GMRS S&4 Voice 
Bands Noise Floor 




960 



990 



1020 



1050 



1080 



1140 



1110 
Frequency (MHz) 

Figure A118: GMRS 3&4, Band 3. 



1170 



1200 



1230 



1260 



A66 




-100 



Bands GMRS 5&6 Idle 
-Bands GMRS 5&6 Voice 
-Bands Noise Floor 



990 1020 1050 1080 1110 1140 

Frequency (MHz) 

Figure A119: GMRS 5 &6, Band 3. 



1170 



1200 



A67 



A.5.4 Band 4 




— Band4GMRS 1&2 Idle 

Band4 GMRS 1&2 Voice 

Band4 Noise Floor 



1579 



1573 1575 1577 
Frequency (MHz) 

Figure A120: GMRS 1&2, Band 4. 



-50 7 



-Band4 GMRS 3&4 Idle 
-Band4 GMRS 3&4 Voice 
Band4 Noise Floor 




1573 1575 1577 

Frequency (MHz) 

Figure A121: GMRS 3&4, Band 4. 



1585 



A68 



-110 



Band4 GMRS 5&6 Idle 
Band4 GMRS 5&6 Voice 
Band4 Noise Floor 




1573 1575 1577 

Frequency (MHz) 

Figure A122: GMRS 5&6, Band 4. 



A69 



A.5.5 Band 5 



-40 



I -60 



-90 



Bands GMRS 1&2 Idle 
-Bands GMRS 1&2 Voice 
Bands Noise Floor 



r* 




vU^4>4" '^'^^'#^W W 



5044 5052 5060 5068 
Frequency (MHz) 

Figure A123: GMRS 1&2, Band 5. 



^tJ^^/1^4/^ 



-30 -1 




Bands GMRS 3&4 Idle 
- Bands GRMS3&4 Voice 
Bands Noise Floor 



5020 5028 5036 5044 5052 5060 5068 

Frequency (MHz) 

Figure A124: GMRS 3&4, Band 5. 



5076 



5084 



5092 



5100 



A70 



- Bands GMRS5&6 Idle 

- Bands GMRS S&6 Voice 
Bands Noise Floor 




5052 5060 5068 

Frequency (MHz) 

Figure A125: GMRS 5&6, Band 5. 



A71 



Appendix B: Measurements and Results of Non-Intentional Transmitters 
Including Computer Laptops and Personal-Digital- Assistants 

The following charts show the results of individual modes tested for each non-intentional transmitter, 
which revealed the best host for each measurement frequency band. These charts were reduced further to 
achieve the maximum radiated emissions envelope for each host device, as discussed and seen in Section 
3.4. Once again the equivalent noise floor was added to the charts to show emissions from the devices 
were above the calibrated noise floor from the measuring instrument. The organization is such that each 
host device is grouped together according to the measurement frequency band. 



B.l Band 1 




-Noise Floor 
Idle 

- Screensaver 

- File transfer 
-CD 

-DVD 






^T' %:'■;" 'ij/' 



109.5 111 112.5 114 

Frequency (MHz) 

Figure Bl: Laptop 1, Band 1. 



Bl 




1.5 111 112.5 114 

Frequency (MHz) 

Figure B2: Laptop 2, Band 1. 




o 

Q. 



1.5 111 112.5 114 

Frequency (MHz) 

Figure B3: Laptop 3, Band 1. 



B2 



-ou 






1 








Noise Floor 








Idle 












i 1 1 1 


Screensaver 








File Transfer 




£ 




CD 




QQ 


1 1 1 


1 
1 








Q. 




1 


ll 11 ' ' ,1^'a ' ' ' ' « '• 




Ji 1 uiiiii Amwi ■■'■ ■ ' ' .. to.M^flii 




l^)0^P^ 


mmLMk 1 .lAi^wv"^ 




Mf/^h .^.Ji .Aa^"'^^*'"'^^ 




/V^ \jv^ IMvV ''^'^^ 1 1 


-120 


i/v*'Yff 



105 



106.5 



108 109.5 111 112.5 114 1 

Frequency (MHz) 

Figure B4: Laptop 4, Band 1. 



117 



118.5 



120 



-50 n 



-60 



-Noise Floor 
-Idle 

- Screensaver 
-File Transfer 
-CD 
DVD 



E 
m 



5 
o 

Q. 






i/W 



*A^^^*^^'^ 



M 




•'HH 



"S -90 

(0 
CC 



-100 



(• ■ If ' V ■" 




1.5 111 112.5 114 

Frequency (MHz) 

Figure B5: Laptop 5, Band I. 



B3 




1.5 111 112.5 114 

Frequency (MHz) 

Figure B6: Laptop 6, Band 1. 




Ill 112.5 114 

Frequency (MHz) 

Figure B7: Laptop 7, Band 1. 



B4 



-50 



E 
m 



5 -80 



■S -90 



-100 \ 



^^ft^V**^S^4/<^*.«^v^ 





1.5 111 112.5 114 

Frequency (MHz) 

Figure B8: Laptop 8, Band 1. 



-50 1 




111 112.5 114 

Frequency (MHz) 

Figure B9: PDA 1, Band 1. 



120 



B5 



5 -80 




-100 



111 112.5 114 

Frequency (MHz) 

Figure BIO: PDA 2, Band 1. 



-50 -1 




-Noise Floor 
Idle 



Iv.K„,.KkaJ/JUJ^ 



105 106.5 108 109.5 111 112.5 114 

Frequency (MHz) 

Figure Bll: PRN, Band 1 



115.5 



118.5 



120 



B6 



B.2 Band 2 



-60 



-120 




-Noise Floor 

Idle 
- Screensaver 
-File Transfer 
-CD 
-DVD 



^$mi!0%iAji4^ 



vvA../^^ 



325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 340 



Figure B12: Laptop 1, Band 2. 



E 

OQ 



■5 -90 




n^-4 '-^^1^^^^ 



- Noise Floor 
-Idle 

- Screensaver 

- File Transfer 
-CD 

DVD 




vvA^V^V^^ 



325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 340 



Figure B13: Laptop 2, Band 2. 



B7 



-50 1 




ilS 



Sd 






-Noise Floor 

Idle 
-Screensaver 
-File Transfer 
-CD 
-DVD 



1076 1105 1134 

Frequency (MHz) 

Figure B14: Laptop 3, Band 2. 



1192 1221 1250 



-50 n 



-60 




%A 



-Noise Floor 
-Idle 

- Screensaver 

- File Transfer 
-CD 

DVD 



mikM^ 



luW 



mwif 



^w^^ 



W^ 



vvA^/vAj^^ 



-120 



325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 340 



Figure B15: Laptop 4, Band 2. 



B8 



E 




- Noise Floor 
-Idle 

- Screensaver 

- Flie Transfer 
-CD 

DVD 



,.( Jn III A . 



iMiffv\mii^^yit0^^^ 



vvAV^vAj^^ 



nw r ^' 






325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 340 



Figure B16: Laptop 5, Band 2. 




- Noise Floor 
Idle 

-Screensaver 

- File Transfer 
-CD 



E 
m 



5 -80 



■S -90 



vvA,,/v^^ 



325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 340 



Figure B17: Laptop 6, Band 2. 



B9 



E 

DQ 



■S -90 




' "VPTn 'vry "'^Mii^ '"^yvrMiV'i vvf 




tetov^ 






vvA.v^Aj^^ 



-120 4 



325 326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 



340 



Figure B18: Laptop 7, Band 2. 



-50 -1 



-70 




Noise Floor 

— Idle 

Screensaver 

File Transfer 

CD 

DVD 



E 
m 

■a 



5 -80 



"S -90 



wMAa 






^aA^/AJAJh^ 



326.5 328 329.5 



331 332.5 334 

Frequency (MHz) 



335.5 337 338.5 



340 



Figure B19: Laptop 8, Band 2. 



BIO 



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REPORT DOCUMENTATION PAGE 



Form Approved 
0MB No. 0704-0188 



Public reporting burden for tliis collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data 
sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other 
aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and 
Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), 
Washington, DC 20503. 



1. AGENCY USE ONLY {Leave blank) 



2. REPORT DATE 

July 2003 



3. REPORT TYPE AND DATES COVERED 

Technical Publication 



4. TITLE AND SUBTITLE 

Portable Wireless LAN Device and Two- Way Radio Threat Assessment for 
Aircraft Navigation Radios 



6. AUTHOR(S) 

Truong X. Nguyen, Sandra V. Koppen, 

Jay J. Ely, Reuben A. Williams, 

Laura J. Smith and Maria Theresa P. Salud 



5. FUNDING NUMBERS 



728-30-10-03 



7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

NASA Langley Research Center 
Hampton, VA 23681-2199 



8. PERFORMING ORGANIZATION 
REPORT NUMBER 



L- 18320 



9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 

National Aeronautics and Space Administration 
Washington, DC 20546-0001 



10. SPONSORING/MONITORING 
AGENCY REPORT NUMBER 

NASA/TP-2003-212438 



11. SUPPLEMENTARY NOTES 



12a. DISTRIBUTION/AVAILABILITY STATEMENT 

Unclassified-Unlimited 

Subject Category 33 Distribution: Standard 

Availability: NASA CAST (301) 621-0390 



12b. DISTRIBUTION CODE 



13. ABSTRACT (Maximum 200 words) 

Measurement processes, data and analysis are provided to address the concern for Wireless Local Area Network 
devices and two-way radios to cause electromagnetic interference to aircraft navigation radio systems. A 
radiated emission measurement process is developed and spurious radiated emissions from various devices are 
characterized using reverberation chambers. Spurious radiated emissions in aircraft radio frequency bands from 
several wireless network devices are compared with baseline emissions from standard computer laptops and 
personal digital assistants. In addition, spurious radiated emission data in aircraft radio frequency bands from 
seven pairs of two-way radios are provided. A description of the measurement process, device modes of 
operation and the measurement results are reported. Aircraft interference path loss measurements were 
conducted on four Boeing 747 and Boeing 737 aircraft for several aircraft radio systems. The measurement 
approach is described and the path loss results are compared with existing data from reference documents, 
standards, and NASA partnerships. In-band on-channel interference thresholds are compiled from an existing 
reference document. Using these data, a risk assessment is provided for interference from wireless network 
devices and two-way radios to aircraft systems, including Localizer, Glideslope, Very High Frequency 
Omnidirectional Range, Microwave Landing System and Global Positioning System. 



14. SUBJECT TERMS 

Electromagnetic, Compatibility, Interference, Susceptibility, Aircraft, Avionics 
Path loss. Emission, PED, Wireless, WLAN, Two-Way Radio, FRS, GMRS 



15. NUMBER OF PAGES 

227 



16. PRICE CODE 



17. SECURITY CLASSIFICATION 
OF REPORT 

Unclassified 



18. SECURITY CLASSIFICATION 
OF THIS PAGE 

Unclassified 



19. SECURITY CLASSIFICATION 
OF ABSTRACT 

Unclassified 



20. LIMITATION 
OF ABSTRACT 
UL 



NSN 7540-01-280-5500 



Standard Form 298 (Rev. 2-89) 

Prescribed by ANSI Std. Z-39-18 
298-102